将一组矢量传递给制服 [英] Passing an array of vectors to a uniform

问题描述

我正在尝试在着色器中实现多个灯光，但是我无法用我的光照数据填充制服。

I am trying to implement multiple lights in my shader but I have trouble to fill the uniform with my light data.

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);
        }
    }
}

仅显示最新信息的代码光：

Code that shows only the latest light:

for (var light in this.lightsDirection) {
    gl.uniform3fv(this.shaderProgram.pointLightingLocationUniform, this.lightsDirection[light]);
    gl.uniform3fv(this.shaderProgram.pointLightingColorUniform, this.lightsColor[light]);
}

作为制服 uPointLightingLocation 是一个大小为16的vec3数组，我认为可以将整个数组传递给制服，但我没有工作解决方案。

As the uniform uPointLightingLocation is 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.

我尝试传递完整的数组 this.lightsColor （没有索引）我看不到任何光。

When I try to pass the complete array this.lightsColor (without the index) I see no light at all.

推荐答案

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（目标，源）。它只是将一个缓冲区从一个地方复制到另一个地方。

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.

假设你的例子只有3个灯，你可以这样统一分配位置：

Assuming your example has only 3 lights, you could assign the location uniform this way:

var locations = [
  1.0, 0, 0,
  0, 1.0, 0,
  0, 0, 0
];
gl.uniform3fv(shaderProgram.pointLightingLocationUniform, locations);

我还建议您在调试此类问题时使用更简单的着色器。在顶点着色器中使用以下内容：

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:

for (int i = 0; i < 3; i++) {
  vColor += uPointLightingLocation[i];
}

片段着色器：

gl_FragColor = vec4(vColor, 1);

然后，如果您的多边形为黄色，则表示它正在工作。

Then, if your polygons are yellow you know it is working.

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