javascript 将向量数组传递给uniform
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Passing an array of vectors to a uniform
提问by WarrenFaith
I am trying to implement multiple lights in my shader but I have trouble to fill the uniform with my light data.
我试图在我的着色器中实现多个灯光，但我无法用我的灯光数据填充制服。
My vertex shader:
我的顶点着色器：
attribute vec3 aVertex;
attribute vec3 aNormal;
attribute vec2 aTexture;
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
uniform mat4 uNMatrix;
uniform vec3 uAmbientColor;
uniform vec3 uPointLightingLocation[16];
uniform vec3 uPointLightingColor[16];
varying vec2 vTexture;
varying vec3 vLightWeighting;
void main(void) {
vec4 mvPosition = uMVMatrix * vec4(aVertex, 1.0);
gl_Position = uPMatrix * mvPosition;
vTexture = aTexture;
int i;
for (i = 0; i < 16; i++) {
vec3 lightDirection = normalize(uPointLightingLocation[i] - mvPosition.xyz);
vec4 transformedNormal = uNMatrix * vec4(aNormal, 1.0);
float directionalLightWeighting = max(dot(transformedNormal.xyz, lightDirection), 0.0);
if (i == 0) {
vLightWeighting = uAmbientColor + uPointLightingColor[i] * directionalLightWeighting;
} else {
vLightWeighting = vLightWeighting * (uAmbientColor + uPointLightingColor[i] * directionalLightWeighting);
}
}
}
Code that shows only the latest light:
仅显示最新灯的代码：
for (var light in this.lightsDirection) {
gl.uniform3fv(this.shaderProgram.pointLightingLocationUniform, this.lightsDirection[light]);
gl.uniform3fv(this.shaderProgram.pointLightingColorUniform, this.lightsColor[light]);
}
As the uniform uPointLightingLocationis a vec3 array with the size of 16, I thought that it would be possible to pass the complete array to the uniform, but I have no working solution.
由于uniformuPointLightingLocation是一个大小为16的vec3数组，我认为可以将完整的数组传递给uniform，但我没有可行的解决方案。
When I try to pass the complete array this.lightsColor(without the index) I see no light at all.
当我尝试传递完整的数组this.lightsColor（没有索引）时，我根本看不到光。
回答by Jacob Foshee
gl.uniform3fv expects a flattened array of floats. Also, you are calling it multiple times with the same uniform location. So, the last one wins. Imagine that uniform3fv is a low-level copy command, and you give it (destination, source). It just copies a buffer from one place to another.
gl.uniform3fv 需要一个扁平的浮点数组。此外，您使用相同的统一位置多次调用它。所以，最后一个获胜。想象一下uniform3fv 是一个低级复制命令，你给它（目的地，源）。它只是将缓冲区从一个地方复制到另一个地方。
Assuming your example has only 3 lights, you could assign the location uniform this way:
假设您的示例只有 3 个灯，您可以通过这种方式分配位置统一：
var locations = [
1.0, 0, 0,
0, 1.0, 0,
0, 0, 0
];
gl.uniform3fv(shaderProgram.pointLightingLocationUniform, locations);
I would also recommend using a more simple shader when you are debugging problems like this. With something like the following in your vertex shader:
我还建议您在调试此类问题时使用更简单的着色器。在您的顶点着色器中使用类似以下内容：
for (int i = 0; i < 3; i++) {
vColor += uPointLightingLocation[i];
}
And fragment shader:
和片段着色器：
gl_FragColor = vec4(vColor, 1);
Then, if your polygons are yellow you know it is working.
然后，如果您的多边形是黄色的，您就知道它正在工作。
