Depth of field WebGL - graphics

I'm new to WebGL and I need to implement Depth of Field. I'm doing this by creating two framebuffers.
On the first framebuffer I render a texture (fbTexture) and a depth texture (depthTex), which are created using 3 shader programs (for different objects).
Then I create a second fragment buffer on which I do horizontal blurring and then draw this texture with the fourth progran on canvas with added vertical blur.
this.frameBuffer = gl.createFramebuffer();
this.dof_frameBuffer = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, this.frameBuffer);
this.texturefb = gl.createTexture();
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, false);
gl.bindTexture(gl.TEXTURE_2D, this.texturefb);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texStorage2D(gl.TEXTURE_2D, 1, gl.RGBA8, gl.drawingBufferWidth, gl.drawingBufferHeight);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, this.texturefb, 0);
this.depthTex = gl.createTexture();
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, false);
gl.bindTexture(gl.TEXTURE_2D, this.depthTex);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texStorage2D(gl.TEXTURE_2D, 1, gl.DEPTH_COMPONENT16, gl.drawingBufferWidth, gl.drawingBufferHeight);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.TEXTURE_2D, this.depthTex, 0);
gl.bindFramebuffer(gl.FRAMEBUFFER, this.dof_frameBuffer);
this.dofTexture = gl.createTexture();
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, false);
gl.bindTexture(gl.TEXTURE_2D, this.dofTexture);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texStorage2D(gl.TEXTURE_2D, 1, gl.RGBA8, gl.drawingBufferWidth, gl.drawingBufferHeight);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, this.dofTexture, 0);
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
So in my draw function I create a square mesh that contains positions and i set all the uniforms:
this.square = gl.createVertexArray();
gl.bindVertexArray(this.square);
gl.bindBuffer(gl.ARRAY_BUFFER, gl.createBuffer());
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
-1, -1,
1, -1,
1, 1,
-1, 1,
]), gl.STATIC_DRAW);
gl.enableVertexAttribArray(0);
gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
let depth = gl.getUniformLocation(program.program, "uDepth");
gl.uniform1i(depth, 5);
gl.bindFramebuffer(gl.FRAMEBUFFER, this.frameBuffer);
gl.viewport(0, 0, this.canvas.width, this.canvas.height);
after I draw all the scene elements (to the fbTexture)
and then at the end of the function:
gl.activeTexture(gl.TEXTURE4);
gl.bindTexture(gl.TEXTURE_2D, this.texturefb);
gl.activeTexture(gl.TEXTURE5);
gl.bindTexture(gl.TEXTURE_2D, this.depthTex);
gl.activeTexture(gl.TEXTURE6);
gl.bindTexture(gl.TEXTURE_2D, this.dofTexture);
program = this.programs.dof;
gl.useProgram(program.program);
let depth = gl.getUniformLocation(program.program, "uDepth");
gl.uniform1i(depth, 5);
gl.bindFramebuffer(gl.FRAMEBUFFER, this.dof_frameBuffer);
gl.clearColor(fog.fogColor[0], fog.fogColor[0], fog.fogColor[0], fog.fogColor[3]);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
program = this.programs.dof;
gl.useProgram(program.program);
gl.bindVertexArray(this.quadVAO);
gl.uniform1f(program.uniforms.uFocusDistance, this.focusDist);
gl.uniform1f(program.uniforms.blurCoef, this.blurCoef);
gl.uniform1f(program.uniforms.uPPM, this.ppm);
gl.uniform2fv(program.uniforms.uDepthRange, this.depthRange);
gl.uniform2fv(program.uniforms.uResolution, this.resolution);
let t = gl.getUniformLocation(program.program, "uColor");
gl.uniform1i(t, 4);
gl.uniform2fv(program.uniforms.uTexelOffset, this.hTexelOffset);
gl.drawArrays(gl.TRIANGLES, 0, 6);
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
gl.clearColor(fog.fogColor[0], fog.fogColor[0], fog.fogColor[0], fog.fogColor[3]);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.viewport(0, 0, gl.drawingBufferWidth, gl.drawingBufferHeight);
gl.uniform1f(program.uniforms.uFocusDistance, this.focusDist);
gl.uniform1f(program.uniforms.blurCoef, this.blurCoef);
gl.uniform1f(program.uniforms.uPPM, this.ppm);
gl.uniform2fv(program.uniforms.uDepthRange, this.depthRange);
gl.uniform2fv(program.uniforms.uResolution, this.resolution);
gl.uniform1i(t, 6);
gl.uniform2fv(program.uniforms.uTexelOffset, this.vTexelOffset);
gl.drawArrays(gl.TRIANGLES, 0, 6);
I use texture units 0-3 for elements in the scene - this is why the depth texture has unit 4.
I tried to follow this program : https://github.com/tsherif/webgl2examples/blob/master/dof.html ,but failed since output on the canvas looks like this :
so it only shows part of the scene. I checked the program multiple times, but i can't find the problem. Does it have to do with texture units or something? And also, is there an easier way to implement depth of field? Any help would be much appreciated!!

Related

Printing text and bitmap using MFC

I need to print some text (using font specified), than print a bitmap, using MFC. I can draw text on bitmap, than print this bitmap, using code below - but I need to print text, and than print bitmap in the bottom. The bitmap must be loaded from file.
CFont j1;
j1.CreateFont(
120, // nHeight
120, // nWidth
0, // nEscapement
0, // nOrientation
FW_NORMAL, // nWeight
FALSE, // bItalic
FALSE, // bUnderline
0, // cStrikeOut
RUSSIAN_CHARSET, // nCharSet
OUT_DEFAULT_PRECIS, // nOutPrecision
CLIP_DEFAULT_PRECIS, // nClipPrecision
DEFAULT_QUALITY, // nQuality
DEFAULT_PITCH | FF_SWISS, // nPitchAndFamily
"Arial"); // lpszFacename // lpszFacename
int w = 600, h = 400;
CClientDC dc(this);
CBitmap bmp;
CDC memdc;
memdc.CreateCompatibleDC(&dc);
bmp.CreateCompatibleBitmap(&dc, w, h);
if (!bmp.Attach(::LoadImage(
::GetModuleHandle(NULL), "D:\\UPM\\BMP\\Login.bmp", IMAGE_BITMAP, 0, 0,
LR_LOADFROMFILE | LR_CREATEDIBSECTION | LR_DEFAULTSIZE))) {
AfxMessageBox(_T("Error loading bitmap!")); return;
}
BITMAP bm;
bmp.GetBitmap(&bm);
auto oldbmp = memdc.SelectObject(bmp);
CFont* pOldFont = memdc.SelectObject(&j1);
//draw on bitmap
///memdc.FillSolidRect(0, 0, w, h, RGB(200, 200, 200));
memdc.SetTextColor(RGB(255, 0, 0));
CRect rc(0, 0, w, h);
memdc.DrawText("qwerty\nrtrtrt\nttttt", &rc, DT_WORDBREAK | DT_EXPANDTABS | DT_CENTER);
///pDC->DrawText(dpu, strRect, DT_WORDBREAK | DT_EXPANDTABS | DT_CENTER);
//dc.BitBlt(0, 0, w, h, &memdc, 0, 0, SRCCOPY);//optional: draw the bitmap on dialog
CPrintDialog pd(false);
if (pd.DoModal() == IDOK)
{
CDC PrintDC;
HDC hdc = pd.GetPrinterDC();
PrintDC.Attach(hdc);
DOCINFO docinfo = { sizeof(docinfo) };
docinfo.lpszDocName = "Print test";
PrintDC.StartDoc(&docinfo);
PrintDC.StartPage();
PrintDC.BitBlt(0, 0, w, h, &memdc, 0, 0, SRCCOPY);
PrintDC.EndPage();
PrintDC.EndDoc();
}
dc.SelectObject(oldbmp);
CClientDC dc(this);
dc.DrawText(...);
...
PrintDC.BitBlt(0, 0, w, h, &memdc, 0, 0, SRCCOPY);
You are drawing text on display's "client DC", then drawing a bitmap on a "printer DC".
Use instead a paint function for everything, and a paint_bitmap function to make things easier.
void paint_bitmap(CDC& dc, CBitmap &bmp, CRect rc)
{
CDC memdc;
memdc.CreateCompatibleDC(&dc);
auto oldbmp = memdc.SelectObject(&bmp);
dc.BitBlt(rc.left, rc.top, rc.Width(), rc.Height(), &memdc, 0, 0, SRCCOPY);
memdc.SelectObject(oldbmp);
}
void paint(CDC& dc)
{
CBitmap bmp;
if (!bmp.Attach(...))...
dc.DrawText(L"text", &rc, ...);
rc.OffsetRect(0, 200);
paint_bitmap(dc, bmp, rc);
}
...
CPrintDialog pd(false);
if (pd.DoModal() == IDOK)
{
HDC hdc = pd.GetPrinterDC();
if (hdc)
{
...
dc.StartPage();
paint(dc); //<- use this for printer or display
dc.EndPage();
}
To print directly to default printer:
CPrintDialog pd(false);
if (pd.GetDefaults() && pd.m_pd.hDC)
{
CDC dc;
dc.Attach(pd.m_pd.hDC);
DOCINFO docinfo = { sizeof(docinfo) };
docinfo.lpszDocName = L"Print test";
dc.StartDoc(&docinfo);
dc.StartPage();
paint(dc);
dc.EndPage();
dc.EndDoc();
}
else
{
MessageBox(L"no default printer...");
}
or if you want a particular printer which you are sure is there, use
HDC hdc = CreateDC(L"WINSPOOL", L"Microsoft Print to PDF", NULL, NULL);
if (hdc)
{
CDC dc;
dc.Attach(hdc);
...
//DeleteDC(hdc); CDC will take care of delete
}

How to properly blend colors across two triangles and remove diagonal smear

I am learning WebGL and I've drawn a full screen quad with colors for each vertex. No lighting or normals or perspective matrix or depth buffer; I'm just drawing a gradient background. This is what I get:
It looks good but I cannot help noticing the diagonal smear from the bottom right to the top left. I feel this is an artifact of linear interpolating the far opposite vertices. I'm drawing two triangles: the bottom left, and the top right. I think I would get similar results using OpenGL instead of WebGL.
Given the same four colors and the same size rectangle, is there a way to render this so the edge between the two triangles isn't so apparent? Maybe more vertices, or a different blending function? I'm not sure exactly what the colors should be at each pixel; I just want to know how to get rid of the diagonal smear.
The issue is the top right triangle has no knowledge of the bottom left corner so the top right triangle is not including any of the blue from the bottom left (and visa versa)
A couple of ways to fix that.
One is to use a 2x2 texture with linear sampling. You have to do some extra math to get the interpolation correct because a texture only interpolates between pixels
+-------+-------+
| | |
| +-------+ |
| | | | |
+---|---+---|---+
| | | | |
| +-------+ |
| | |
+-------+-------+
Above is a 4 pixel texture stretched to 14 by 6. Sampling happens between pixels so only this center area will get the gradient. Outside that area would be sampled with pixels outside the texture so using CLAMP_TO_EDGE or on the opposite side of the texture using REPEAT.
const gl = document.querySelector('canvas').getContext('webgl');
const tl = [254, 217, 138];
const tr = [252, 252, 252];
const bl = [18, 139, 184];
const br = [203, 79, 121];
const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1);
gl.texImage2D(
gl.TEXTURE_2D,
0, // mip level
gl.RGB, // internal format
2, // width,
2, // height,
0, // border
gl.RGB, // format
gl.UNSIGNED_BYTE, // type
new Uint8Array([...bl, ...br, ...tl, ...tr]));
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
const vs = `
attribute vec4 position;
attribute vec2 texcoord;
varying vec2 v_texcoord;
void main() {
gl_Position = position;
v_texcoord = texcoord;
}
`;
const fs = `
precision mediump float;
varying vec2 v_texcoord;
const vec2 texSize = vec2(2, 2); // could pass this in
uniform sampler2D tex;
void main() {
gl_FragColor = texture2D(tex,
(v_texcoord * (texSize - 1.0) + 0.5) / texSize);
}
`;
const program = twgl.createProgram(gl, [vs, fs]);
const positionLoc = gl.getAttribLocation(program, 'position');
const texcoordLoc = gl.getAttribLocation(program, 'texcoord');
function createBufferAndSetupAttribute(loc, data) {
const buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(data), gl.STATIC_DRAW);
gl.enableVertexAttribArray(loc);
gl.vertexAttribPointer(
loc,
2, // 2 elements per iteration
gl.FLOAT, // type of data in buffer
false, // normalize
0, // stride
0, // offset
);
}
createBufferAndSetupAttribute(positionLoc, [
-1, -1,
1, -1,
-1, 1,
-1, 1,
1, -1,
1, 1,
]);
createBufferAndSetupAttribute(texcoordLoc, [
0, 0,
1, 0,
0, 1,
0, 1,
1, 0,
1, 1,
]);
gl.useProgram(program);
// note: no need to set sampler uniform as it defaults
// to 0 which is what we'd set it to anyway.
gl.drawArrays(gl.TRIANGLES, 0, 6);
canvas { border: 1px solid black; }
<canvas></canvas>
<script src="https://twgljs.org/dist/4.x/twgl.min.js"></script>
Note: to see what I mean about the extra math needed for the texture coordinates here is the same example without the extra math
const gl = document.querySelector('canvas').getContext('webgl');
const tl = [254, 217, 138];
const tr = [252, 252, 252];
const bl = [18, 139, 184];
const br = [203, 79, 121];
const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1);
gl.texImage2D(
gl.TEXTURE_2D,
0, // mip level
gl.RGB, // internal format
2, // width,
2, // height,
0, // border
gl.RGB, // format
gl.UNSIGNED_BYTE, // type
new Uint8Array([...bl, ...br, ...tl, ...tr]));
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
const vs = `
attribute vec4 position;
attribute vec2 texcoord;
varying vec2 v_texcoord;
void main() {
gl_Position = position;
v_texcoord = texcoord;
}
`;
const fs = `
precision mediump float;
varying vec2 v_texcoord;
uniform sampler2D tex;
void main() {
gl_FragColor = texture2D(tex, v_texcoord);
}
`;
const program = twgl.createProgram(gl, [vs, fs]);
const positionLoc = gl.getAttribLocation(program, 'position');
const texcoordLoc = gl.getAttribLocation(program, 'texcoord');
function createBufferAndSetupAttribute(loc, data) {
const buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(data), gl.STATIC_DRAW);
gl.enableVertexAttribArray(loc);
gl.vertexAttribPointer(
loc,
2, // 2 elements per iteration
gl.FLOAT, // type of data in buffer
false, // normalize
0, // stride
0, // offset
);
}
createBufferAndSetupAttribute(positionLoc, [
-1, -1,
1, -1,
-1, 1,
-1, 1,
1, -1,
1, 1,
]);
createBufferAndSetupAttribute(texcoordLoc, [
0, 0,
1, 0,
0, 1,
0, 1,
1, 0,
1, 1,
]);
gl.useProgram(program);
// note: no need to set sampler uniform as it defaults
// to 0 which is what we'd set it to anyway.
gl.drawArrays(gl.TRIANGLES, 0, 6);
canvas { border: 1px solid black; }
<canvas></canvas>
<script src="https://twgljs.org/dist/4.x/twgl.min.js"></script>
Also of course, rather than do the math in the fragment shader we could fix the texture coordinates in JavaScript
const gl = document.querySelector('canvas').getContext('webgl');
const tl = [254, 217, 138];
const tr = [252, 252, 252];
const bl = [18, 139, 184];
const br = [203, 79, 121];
const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1);
gl.texImage2D(
gl.TEXTURE_2D,
0, // mip level
gl.RGB, // internal format
2, // width,
2, // height,
0, // border
gl.RGB, // format
gl.UNSIGNED_BYTE, // type
new Uint8Array([...bl, ...br, ...tl, ...tr]));
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
const vs = `
attribute vec4 position;
attribute vec2 texcoord;
varying vec2 v_texcoord;
void main() {
gl_Position = position;
v_texcoord = texcoord;
}
`;
const fs = `
precision mediump float;
varying vec2 v_texcoord;
uniform sampler2D tex;
void main() {
gl_FragColor = texture2D(tex, v_texcoord);
}
`;
const program = twgl.createProgram(gl, [vs, fs]);
const positionLoc = gl.getAttribLocation(program, 'position');
const texcoordLoc = gl.getAttribLocation(program, 'texcoord');
function createBufferAndSetupAttribute(loc, data) {
const buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(data), gl.STATIC_DRAW);
gl.enableVertexAttribArray(loc);
gl.vertexAttribPointer(
loc,
2, // 2 elements per iteration
gl.FLOAT, // type of data in buffer
false, // normalize
0, // stride
0, // offset
);
}
createBufferAndSetupAttribute(positionLoc, [
-1, -1,
1, -1,
-1, 1,
-1, 1,
1, -1,
1, 1,
]);
createBufferAndSetupAttribute(texcoordLoc, [
0.25, 0.25,
0.75, 0.25,
0.25, 0.75,
0.25, 0.75,
0.75, 0.25,
0.75, 0.75,
]);
gl.useProgram(program);
// note: no need to set sampler uniform as it defaults
// to 0 which is what we'd set it to anyway.
gl.drawArrays(gl.TRIANGLES, 0, 6);
canvas { border: 1px solid black; }
<canvas></canvas>
<script src="https://twgljs.org/dist/4.x/twgl.min.js"></script>
Another way is to do the interpolation yourself based on those corners (which is effectively doing what the texture sampler is doing in the previous example, bi-linear interpolation of the 4 colors).
const gl = document.querySelector('canvas').getContext('webgl');
const tl = [254/255, 217/255, 138/255];
const tr = [252/255, 252/255, 252/255];
const bl = [ 18/255, 139/255, 184/255];
const br = [203/255, 79/255, 121/255];
const vs = `
attribute vec4 position;
attribute vec2 texcoord;
varying vec2 v_texcoord;
void main() {
gl_Position = position;
v_texcoord = texcoord;
}
`;
const fs = `
precision mediump float;
varying vec2 v_texcoord;
uniform vec3 tl;
uniform vec3 tr;
uniform vec3 bl;
uniform vec3 br;
void main() {
vec3 l = mix(bl, tl, v_texcoord.t);
vec3 r = mix(br, tr, v_texcoord.t);
vec3 c = mix(l, r, v_texcoord.s);
gl_FragColor = vec4(c, 1);
}
`;
const program = twgl.createProgram(gl, [vs, fs]);
const positionLoc = gl.getAttribLocation(program, 'position');
const texcoordLoc = gl.getAttribLocation(program, 'texcoord');
const tlLoc = gl.getUniformLocation(program, 'tl');
const trLoc = gl.getUniformLocation(program, 'tr');
const blLoc = gl.getUniformLocation(program, 'bl');
const brLoc = gl.getUniformLocation(program, 'br');
function createBufferAndSetupAttribute(loc, data) {
const buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(data), gl.STATIC_DRAW);
gl.enableVertexAttribArray(loc);
gl.vertexAttribPointer(
loc,
2, // 2 elements per iteration
gl.FLOAT, // type of data in buffer
false, // normalize
0, // stride
0, // offset
);
}
createBufferAndSetupAttribute(positionLoc, [
-1, -1,
1, -1,
-1, 1,
-1, 1,
1, -1,
1, 1,
]);
createBufferAndSetupAttribute(texcoordLoc, [
0, 0,
1, 0,
0, 1,
0, 1,
1, 0,
1, 1,
]);
gl.useProgram(program);
gl.uniform3fv(tlLoc, tl);
gl.uniform3fv(trLoc, tr);
gl.uniform3fv(blLoc, bl);
gl.uniform3fv(brLoc, br);
gl.drawArrays(gl.TRIANGLES, 0, 6);
canvas { border: 1px solid black; }
<canvas></canvas>
<script src="https://twgljs.org/dist/4.x/twgl.min.js"></script>
Number of dimensions
You should be passing the 2D coordinate space of the quad to the fragment shader rather than the one dimensional (per channel) color space.
Then in the fragment shader you can do the color interpolation in 2D space removing the color artifact due to the diagonal line interpolating in 1D.
The shader snippet for linear color interpolation, where coord2D is the 2D coordinate space
pixel = vec4(vec3(mix(
mix(colors[0], colors[1], coord2D.x),
mix(colors[2], colors[3], coord2D.x),
coord2D.y
)), 1);
Improved color interpolation
When interpolating colors by their RGB values the results can visually darken between opposing hues.
An easy fix is to use a closer approximation of the sRGB color model by interpolating between the squares of the color channel values. The final output is the square root of the interpolated values.
The interpolation snippet.
pixel = vec4(sqrt(vec3(mix(
mix(colors[0], colors[1], coord2D.x),
mix(colors[2], colors[3], coord2D.x),
coord2D.y
))) / 255.0, 1);
Note that the color channel values in the uniform colors are in logarithmic space. [R^2, G^2, B^2] and thus range from 0 to 65025.
Example
In the example click the canvas to switch between interpolation methods.
You will note that when using approx ~sRGB that the brightness in the center of the canvas out towards the center edges does not dip as much below the perceivable brightness at the corners.
Also note that the balance of the transition from the bottom blue and redish to the top orange and white moves down closer the the center. This is because interpolating the RGB model will darken colors that have strong components from 2 or more channels, Reds, greens, blues and blacks will dominate over yellows, cyans, magentas and whites making the interpolation seem to shift and stretch out the RGB primaries.
var program, colorsLoc, modelLoc, loc, text = " interpolation. Click for ", model = "RGB"; // or sRGB
const vertSrc = `#version 300 es
in vec2 verts;
out vec2 coord2D;
void main() {
coord2D = verts * 0.5 + 0.5; // convert to quad space 0,0 <=> 1, 1
gl_Position = vec4(verts, 1, 1);
}`;
const fragSrc = `#version 300 es
#define channelMax 255.0
// color location indexes
#define TR 3
#define TL 2
#define BR 1
#define BL 0
precision mediump float;
uniform vec3 colors[4];
uniform bool isRGB;
in vec2 coord2D;
out vec4 pixel;
void main() {
if (isRGB) {
pixel = vec4(vec3(mix(
mix(colors[BL], colors[BR], coord2D.x),
mix(colors[TL], colors[TR], coord2D.x),
coord2D.y
)) / channelMax, 1);
} else {
pixel = vec4(vec3(sqrt(mix(
mix(colors[BL], colors[BR], coord2D.x),
mix(colors[TL], colors[TR], coord2D.x),
coord2D.y
))) / channelMax, 1);
}
}`;
const fArr = arr => new Float32Array(arr);
const colors = [64,140,190, 224,81,141, 247,223,140, 245,245,245];
const gl = canvas.getContext("webgl2", {premultipliedAlpha: false, antialias: false, alpha: false});
addEventListener("resize", draw);
addEventListener("click", draw);
setup();
draw();
function compileShader(src, type, shader = gl.createShader(type)) {
gl.shaderSource(shader, src);
gl.compileShader(shader);
return shader;
}
function setup() {
program = gl.createProgram();
gl.attachShader(program, compileShader(vertSrc, gl.VERTEX_SHADER));
gl.attachShader(program, compileShader(fragSrc, gl.FRAGMENT_SHADER));
gl.linkProgram(program);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, gl.createBuffer());
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint8Array([0,1,2,0,2,3]), gl.STATIC_DRAW);
gl.bindBuffer(gl.ARRAY_BUFFER, gl.createBuffer());
gl.bufferData(gl.ARRAY_BUFFER, fArr([-1,-1,1,-1,1,1,-1,1]), gl.STATIC_DRAW);
gl.enableVertexAttribArray(loc = gl.getAttribLocation(program, "verts"));
gl.vertexAttribPointer(loc, 2, gl.FLOAT, false, 0, 0);
colorsLoc = gl.getUniformLocation(program, "colors");
modelLoc = gl.getUniformLocation(program, "isRGB");
gl.useProgram(program);
}
function draw() {
[info.textContent, model] = model != "RGB"? [`RGB${text}~sRGB.`, "RGB"]: [`~sRGB${text}RGB.`, "~sRGB"];
if (canvas.width !== innerWidth || canvas.height !== innerHeight) {
[canvas.width, canvas.height] = [innerWidth, innerHeight];
gl.viewport(0, 0, canvas.width, canvas.height);
}
gl.uniform3fv(colorsLoc, fArr(colors.map(v => model=="RGB"? v: v*v)), 0, 12);
gl.uniform1i(modelLoc, model=="RGB");
gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_BYTE, 0);
}
body {
padding: 0px;
margin: 0px;
font-family: arial;
color: white;
}
canvas {
position: absolute;
top: 0px;
left: 0px;
}
h2 {
position: absolute;
bottom: 0px;
left: 0px;
right: 0px;
text-align: center;
}
<canvas id="canvas"></canvas>
<h2 id="info"></h2>

Mismatch between print preview and real print output

I want to print a bitmap. To avoid printing small bitmap I set CScrollView mode as MM_LOMETRIC with sizes 3830 x 1995. I have created the bitmap and made the bitblt to the screen. There were everythig just like I want on the screen and on the print preview but when I printed the document I've got very bad result.
The same picture on print preview.
It seems to me that printer does not see a bitmap the same way as print preview does.
Pay attantion that the first ractangle puts directly on the DC and memDC puts into it.
Are there any ideas how to fix this mismatch between print previw and the real printing?
Project files
void OnDraw()
{
CPen pen;
pen.CreatePen(PS_SOLID, 1, RGB(0, 0, 0));
CPen* OldPen = pDC->SelectObject(&pen);
CRect rcView;
GetClientRect(rcView);
int iClientWidth = rcView.right;
int iClientHeight = rcView.bottom;
int iMemWidth = 1900;
int iMemHeight = 950;
CDC memDC;
CBitmap memBitmap;
memDC.CreateCompatibleDC(pDC);
memBitmap.CreateCompatibleBitmap(pDC, iMemWidth, iMemHeight);
memDC.SelectObject(&memBitmap);
memDC.SetMapMode(MM_LOMETRIC);
CPen pen1;
pen1.CreatePen(PS_SOLID, 3, RGB(0, 0, 0));
memDC.SelectObject(&pen1);
CBrush brBK;
brBK.CreateSolidBrush(RGB(255, 255, 255));
memDC.SelectObject(&brBK);
RECT rc;
rc.left = 0;
rc.top = 0;
rc.right = iMemWidth;
rc.bottom = iMemHeight;
memDC.FillRect(&rc, &brBK);
memDC.Rectangle(rc.left, rc.top, rc.right, -rc.bottom);
memDC.MoveTo(0, 0);
memDC.LineTo(1900, -950);
memDC.MoveTo(0, -950);
memDC.LineTo(200, -750);
CFont font;
font.CreateFont(
50, // nHeight
0, // nWidth
0, // nEscapement
0, // nOrientation
FW_NORMAL, // nWeight
FALSE, // bItalic
FALSE, // bUnderline
0, // cStrikeOut
ANSI_CHARSET, // nCharSet
OUT_DEFAULT_PRECIS, // nOutPrecision
CLIP_DEFAULT_PRECIS, // nClipPrecision
DEFAULT_QUALITY, // nQuality
DEFAULT_PITCH | FF_SWISS, // nPitchAndFamily
_T("Arial"));
memDC.SelectObject(&font);
memDC.TextOut(100, -100, _T("Hello"));
pDC->BitBlt(10, -10, iMemWidth, -iMemHeight, &memDC, 0, 0, SRCCOPY);
font.DeleteObject();
brBK.DeleteObject();
memDC.DeleteDC();
memBitmap.DeleteObject();
pen.DeleteObject();
pen1.DeleteObject();
}
void OnInitialUpdate()
{
CScrollView::OnInitialUpdate();
CSize sizeTotal;
sizeTotal.cx = 3830;
sizeTotal.cy = 1995;
SetScrollSizes(MM_LOMETRIC, sizeTotal);
}

Processing: How do I make a triggered sound stop?

When the picture of the woman moves over one of the moving hexagons, a few things happen. I have a sound(police) that is triggered when she touches one of them. The problem is that the sound continues even when she is not on the hexagon even longer. Plus, if she touches the hexagon again the sound is triggered again over the first sound. So now I have a mess of the same sound playing over each other.
I want her to move over a hexagon, the sound is triggered. When she moves off the hexagon the sound instantly stops until she moves over it again.
Here's the code:
import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.effects.*;
import ddf.minim.signals.*;
import ddf.minim.spi.*;
import ddf.minim.ugens.*;
Minim minim;
AudioSample police;
color underhex = color(255, 0, 0);
PImage woman;
float headX = 50, headY = 50;
float ss = 0;
float fade=30, fade2=9;
PShape hexagon, trapezoid, trapezoid2;
float[] hspeed = {2.4, 2.8, 3.2, 3.6, 4, 4.4, 4.8};
float[] g = {0, 0, 0, 0, 0, 0, 0};
void setup() {
size(900, 600, P3D);
background(250);
noStroke();
minim = new Minim(this);
police = minim.loadSample("PoliceSiren.mp3", 1024);
hexagon = createShape(GROUP);
PShape trapezoid = createShape(QUAD, 100, 50, 325, 50, 375, 180, 50, 180);
PShape trapezoid2 = createShape(QUAD, 50, 180, 375, 180, 325, 320, 100, 320);
hexagon.scale(0.25);
hexagon.addChild(trapezoid);
hexagon.addChild(trapezoid2);
hexagon.setFill(color(255, 0, 0, 50));
woman = loadImage("woman.png");
}
void draw() {
background(250);
image(woman, headX, headY, 70, 81);
for (int p = 0; p < 5; p++) {
pushMatrix();
translate(g[p], 120*p);
underhex = get(int(g[p])+30, int(120*p)+30);
shape(hexagon, 0, 0);
//ellipse(width/2,height/2,50,50);
popMatrix();
g[p]+=hspeed[p];
if (int(g[p]) > 830 || int(g[p]) < 0) {
hspeed[p] *= -1;
}
if (red(underhex) < 20 && green(underhex) < 20 && blue(underhex) < 20) {
println("she's here"+random(5));
fill(0, 240);
rect(0, 0, 900, 600);
strokeWeight(30);
fill(0, 0, 255, fade);
stroke(0, 0, 255, fade);
ellipse(250, 200, 100, 100);
fill(255, 0, 0, fade);
stroke(255, 0, 0, fade);
ellipse(290, 330, 100, 100);
fill(0, 0, 255, fade);
stroke(0, 0, 255, fade);
ellipse(680, 200, 100, 100);
fill(255, 0, 0, fade);
stroke(255, 0, 0, fade);
ellipse(640, 330, 100, 100);
noStroke();
police.trigger();
fade += fade2;
if (fade<0 || fade>255) {
fade2 *= -1;
}
}
}
if (keyPressed) {
if (keyCode == UP) {
headY-=random(2, 6);
} else if (keyCode == DOWN) {
headY+=random(2, 6);
} else if (keyCode == LEFT) {
headX-=random(2, 6);
} else if (keyCode == RIGHT) {
headX+=random(2, 6);
}
}
}
Try using AudioPlayer instead of AudioSample. It provides isPlaying() which is handy to check if the sound is already playing or not.
e.g.
//at the top
AudioPlayer police;
//in setup()
police = minim.loadFile("PoliceSiren.mp3");
//in draw() instead of police.trigger()
if(!police.isPlaying() || ){
police.play();
}
Update
It sounds like looping is what you're after:
import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.effects.*;
import ddf.minim.signals.*;
import ddf.minim.spi.*;
import ddf.minim.ugens.*;
Minim minim;
AudioPlayer police;
color underhex = color(255, 0, 0);
PImage woman;
float headX = 50, headY = 50;
float ss = 0;
float fade=30, fade2=9;
PShape hexagon, trapezoid, trapezoid2;
float[] hspeed = {2.4, 2.8, 3.2, 3.6, 4, 4.4, 4.8};
float[] g = {0, 0, 0, 0, 0, 0, 0};
void setup() {
size(900, 600, P3D);
background(250);
noStroke();
minim = new Minim(this);
//police = minim.loadSample("PoliceSiren.mp3", 1024);
police = minim.loadFile("PoliceSiren.mp3");
hexagon = createShape(GROUP);
PShape trapezoid = createShape(QUAD, 100, 50, 325, 50, 375, 180, 50, 180);
PShape trapezoid2 = createShape(QUAD, 50, 180, 375, 180, 325, 320, 100, 320);
hexagon.scale(0.25);
hexagon.addChild(trapezoid);
hexagon.addChild(trapezoid2);
hexagon.setFill(color(255, 0, 0, 50));
woman = loadImage("woman.png");
}
void draw() {
background(250);
image(woman, headX, headY, 70, 81);
for (int p = 0; p < 5; p++) {
pushMatrix();
translate(g[p], 120*p);
underhex = get(int(g[p])+30, int(120*p)+30);
shape(hexagon, 0, 0);
//ellipse(width/2,height/2,50,50);
popMatrix();
g[p]+=hspeed[p];
if (int(g[p]) > 830 || int(g[p]) < 0) {
hspeed[p] *= -1;
}
if (red(underhex) < 20 && green(underhex) < 20 && blue(underhex) < 20) {
println("she's here"+random(5));
fill(0, 240);
rect(0, 0, 900, 600);
strokeWeight(30);
fill(0, 0, 255, fade);
stroke(0, 0, 255, fade);
ellipse(250, 200, 100, 100);
fill(255, 0, 0, fade);
stroke(255, 0, 0, fade);
ellipse(290, 330, 100, 100);
fill(0, 0, 255, fade);
stroke(0, 0, 255, fade);
ellipse(680, 200, 100, 100);
fill(255, 0, 0, fade);
stroke(255, 0, 0, fade);
ellipse(640, 330, 100, 100);
noStroke();
if(!police.isPlaying()){
police.loop();
}
fade += fade2;
if (fade<0 || fade>255) {
fade2 *= -1;
}
}else{
if(police.isLooping()){
police.pause();
}
}
}
if (keyPressed) {
if (keyCode == UP) {
headY-=random(2, 6);
} else if (keyCode == DOWN) {
headY+=random(2, 6);
} else if (keyCode == LEFT) {
headX-=random(2, 6);
} else if (keyCode == RIGHT) {
headX+=random(2, 6);
}
}
}
Also checkout mute(),unmute(),isMuted(): perhaps you can keep the sound looping but muted and only unmute when the collision happens

How do I draw a pixmap to root window with xcb?

I'm trying to write a window manager with a wallpaper switcher:
void smoke_change_background(smoke_wm_state_t *config, char *desktop) {
struct smoke_desktop_list_element_t *node = smoke_desktop_list_node(config->tree, desktop);
if (node->background != 0) {
xcb_intern_atom_reply_t *xpmap = xcb_intern_atom_reply(config->connection,
xcb_intern_atom(config->connection,
false,
strlen("_X_ROOTPMAP_ID"),
"_X_ROOTPMAP_ID"),
NULL);
xcb_intern_atom_reply_t *esetr = xcb_intern_atom_reply(config->connection,
xcb_intern_atom(config->connection,
false,
strlen("ESETROOT_PMAP_ID"),
"ESETROOT_PMAP_ID"),
NULL);
xcb_get_property_reply_t *xrepl = xcb_get_property_reply(config->connection,
xcb_get_property(config->connection,
0,
config->screen->root,
xpmap->atom,
XCB_ATOM_PIXMAP,
0,
32),
NULL);
uint32_t *xp = (uint32_t*) xcb_get_property_value(xrepl);
xcb_get_property_reply_t *erepl = xcb_get_property_reply(config->connection,
xcb_get_property(config->connection,
0,
config->screen->root,
esetr->atom,
XCB_ATOM_PIXMAP,
0, 32),
NULL);
uint32_t *ep = (uint32_t*) xcb_get_property_value(erepl);
xcb_change_property(config->connection,
XCB_PROP_MODE_REPLACE,
config->screen->root,
xpmap->atom,
XCB_ATOM_PIXMAP,
32, 1,
(void*) &node->background);
xcb_change_property(config->connection,
XCB_PROP_MODE_REPLACE,
config->screen->root,
esetr->atom,
XCB_ATOM_PIXMAP,
32, 1,
(void*) &node->background);
xcb_free_pixmap(config->connection, *xp);
xcb_free_pixmap(config->connection, *ep);
uint32_t values[1];
values[0] = node->background;
xcb_change_window_attributes(config->connection, config->screen->root, XCB_CW_BACK_PIXMAP, values);
xcb_clear_area(config->connection, false, config->screen->root, 0, 0, 0, 0);
xcb_flush(config->connection);
}
}
This code should change the root's pixmap and it should be displayed in my Xephyr window, but it is not. What's wrong?

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