我正在尝试使用webgl2纹理将Uint16Array
渲染到浏览器中的图像。我有一个Uint8Array
的工作示例,由于webgl的学习曲线很艰难,因此正在努力升级到16位。
工作8位小提琴(与以下代码段相同): Uint8Array
http://jsfiddle.net/njxvftc9/2/
不起作用的16位尝试: Uint16Array
http://jsfiddle.net/njxvftc9/3/
// image data
var w = 128;
var h = 128;
var size = w * h * 4;
var img = new Uint8Array(size); // need Uint16Array
for (var i = 0; i < img.length; i += 4) {
img[i + 0] = 255; // r
img[i + 1] = i/64; // g
img[i + 2] = 0; // b
img[i + 3] = 255; // a
}
// program
var canvas = document.getElementById('cv');
var gl = canvas.getContext('webgl2');
var program = gl.createProgram();
//var color_buffer_float_16ui = gl.getExtension('EXT_color_buffer_float'); // add for 16-bit
// texture
var tex = gl.createTexture(); // create empty texture
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texImage2D(
gl.TEXTURE_2D, // target
0, // mip level
gl.RGBA, // internal format -> gl.RGBA16UI
w, h, // width and height
0, // border
gl.RGBA, //format -> gm.RGBA_INTEGER
gl.UNSIGNED_BYTE, // type -> gl.UNSIGNED_SHORT
img // texture data
);
// buffer
var buffer = gl.createBuffer();
var bufferData = new Float32Array([
-1, -1,
1, -1,
1, 1,
1, 1,
-1, 1,
-1, -1
]);
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, bufferData, gl.STATIC_DRAW);
// shaders
program.vs = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(program.vs,
"attribute vec4 vertex;\n" + // incoming pixel input?
"varying vec2 pixelCoordinate;\n" + // variable used to pass position to fragment shader
"void main(){\n" +
" gl_Position = vertex;\n" + // set pixel output position to incoming position (pass through)
" pixelCoordinate = vertex.xy*0.5+0.5;\n" + // set coordinate for fragment shader
"}\n");
program.fs = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(program.fs,
"precision highp float;\n" + // ?
"uniform sampler2D tex;\n" + // ?
"varying vec2 pixelCoordinate;\n" + // receive pixel position from vertex shader
"void main(){\n" +
" gl_FragColor = texture2D(tex, pixelCoordinate);\n" + // lookup color in texture image at coordinate position and set color to
"}\n");
gl.compileShader(program.vs);
gl.compileShader(program.fs);
gl.attachShader(program,program.vs);
gl.attachShader(program,program.fs);
gl.deleteShader(program.vs);
gl.deleteShader(program.fs);
// program
gl.bindAttribLocation(program, 0, "vertex");
gl.linkProgram(program);
gl.useProgram(program);
gl.enableVertexAttribArray(0);
gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT);
gl.drawArrays(gl.TRIANGLES, 0, 6); // execute program
<canvas id="cv" width="100" height="100"></canvas>
我尝试了许多其他技术,引用了规范,尝试在着色器中转换为浮点,并且尝试将此处看到的方法组合在一起:Render to 16bits unsigned integer 2D texture in WebGL2没有成功。
我更喜欢 Vanilla js,但是只要输入是
Uint16Array
,着色器就可以输出任何格式( float 等),但可以使用twgl或three.js之类的库。任何在webgl2方面有更多经验的人都可以向我指出正确的方向,或者在这里提供有效的示例提琴吗?我的代码中是否有一个简单的错误,我是否错过了一个更大的概念,这是否可能?任何帮助是极大的赞赏!
最佳答案
如果要将16位数据放入纹理中,则需要选择16位纹理内部格式。查看the list of internal formats,您对RGBA的选择是
gl.RGBA16I // 16bit integers
gl.RGBA16UI // 16bit unsigned integers
gl.RGBA16F // 16bit half floats
您似乎选择了
gl.RGBA16UI
要在着色器中访问该纹理,请在此行
uniform sampler2D tex;
必须改变这个
uniform usampler2D tex;
该语法仅在GLSL 3.00中可用,因此您需要在两个着色器的顶部添加
#version 300 es
。切换到
#version 300 es
也意味着other syntax changes。 attribute
变成in
,varying
变成顶点着色器中的out
,而片段着色器中的in
。 gl_FragColor
消失,您必须声明自己的输出,例如out vec4 fooColor;
。 texture2D
也变成texture
您不能对整数纹理使用过滤,因此这两行
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
需要更改为
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
当您从纹理中获取数据时,它将是无符号整数,因此此行
gl_FragColor = texture2D(tex, pixelCoordinate);
最终会变成类似
out vec4 fooColor; // named this fooColor to make it clear you pick the name
void main() {
uvec4 unsignedIntValues = texture(tex, pixelCoordinate);
vec4 floatValues0To65535 = vec4(unsignedIntValues);
vec4 colorValues0To1 = floatValues0To65535 / 65535.0;
fooColor = colorValues0To1;
}
当然,您可以将数学缩短为一行
fooColor = vec4(texture(tex, pixelCoordinate)) / 65535.0;
例:
// image data
var w = 128;
var h = 128;
var size = w * h * 4;
var img = new Uint16Array(size); // need Uint16Array
for (var i = 0; i < img.length; i += 4) {
img[i + 0] = 65535; // r
img[i + 1] = i/64 * 256; // g
img[i + 2] = 0; // b
img[i + 3] = 65535; // a
}
// program
var canvas = document.getElementById('cv');
var gl = canvas.getContext('webgl2');
var program = gl.createProgram();
//var color_buffer_float_16ui = gl.getExtension('EXT_color_buffer_float'); // add for 16-bit
// texture
var tex = gl.createTexture(); // create empty texture
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texImage2D(
gl.TEXTURE_2D, // target
0, // mip level
gl.RGBA16UI, // internal format -> gl.RGBA16UI
w, h, // width and height
0, // border
gl.RGBA_INTEGER, //format -> gm.RGBA_INTEGER
gl.UNSIGNED_SHORT, // type -> gl.UNSIGNED_SHORT
img // texture data
);
// buffer
var buffer = gl.createBuffer();
var bufferData = new Float32Array([
-1, -1,
1, -1,
1, 1,
1, 1,
-1, 1,
-1, -1
]);
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, bufferData, gl.STATIC_DRAW);
// shaders
program.vs = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(program.vs, `#version 300 es
in vec4 vertex; // incoming pixel input?
out vec2 pixelCoordinate; // variable used to pass position to fragment shader
void main(){
gl_Position = vertex; // set pixel output position to incoming position (pass through)
pixelCoordinate = vertex.xy*0.5+0.5; // set coordinate for fragment shader
}
`);
program.fs = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(program.fs, `#version 300 es
precision highp float; // ?
uniform highp usampler2D tex; // ?
in vec2 pixelCoordinate; // receive pixel position from vertex shader
out vec4 fooColor;
void main() {
uvec4 unsignedIntValues = texture(tex, pixelCoordinate);
vec4 floatValues0To65535 = vec4(unsignedIntValues);
vec4 colorValues0To1 = floatValues0To65535 / 65535.0;
fooColor = colorValues0To1;
}
`);
gl.compileShader(program.vs);
checkCompileError(program.vs);
gl.compileShader(program.fs);
checkCompileError(program.fs);
function checkCompileError(s) {
if (!gl.getShaderParameter(s, gl.COMPILE_STATUS)) {
console.error(gl.getShaderInfoLog(s));
}
}
gl.attachShader(program,program.vs);
gl.attachShader(program,program.fs);
gl.deleteShader(program.vs);
gl.deleteShader(program.fs);
// program
gl.bindAttribLocation(program, 0, "vertex");
gl.linkProgram(program);
gl.useProgram(program);
gl.enableVertexAttribArray(0);
gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT);
gl.drawArrays(gl.TRIANGLES, 0, 6); // execute program
<canvas id="cv" width="100" height="100"></canvas>