OpenGL ES 3 实例渲染失败，但适用于桌面

Question

我能够在具有 GLSL 330 内核的桌面上使用实例渲染，但我无法在 Android 上运行相同的 C++ 代码（使用 SDL2 和 NDK 构建系统和 Android Studio）。

logcat错误如下图：

-18 15:49:57.264 20996-21026/package I/SDL/APP: shaders/mobile/sceneShader.frag.glsl compiled successfully
10-18 15:49:57.274 20996-21026/package I/SDL/APP: Program link failed: --From Vertex Shader:
10-18 15:49:57.274 20996-21026/packageI/SDL/APP: linker error: multiple attribute attempt to bind at same location 
10-18 15:49:57.274 20996-21026/packageI/SDL/APP: --From Fragment Shader:
10-18 15:49:57.274 20996-21026/package I/SDL/APP: linker error: multiple attribute attempt to bind at same location 

我的桌面和移动着色器代码是相同的，除了文件顶部的#version 行（分别指定 es 或桌面版本）。

我的移动着色器代码如下所示：

#version 300 es

precision mediump float;

// attribute data
layout (location = 0) in vec3 VertexPosition;
layout (location = 1) in vec2 VertexTexCoord;
layout (location = 2) in vec3 VertexNormal;
layout (location = 3) in mat4 InstanceTransform; // used for translating the positions of instance renders

// varying data
layout (location = 0) out vec3 vPosition;
layout (location = 1) out vec2 vTexCoord0;
layout (location = 2) out vec2 vTexCoord1;
layout (location = 3) out vec3 vTexSkyboxCoord;
layout (location = 4) out vec3 vNormal;
layout (location = 5) out vec3 vClampColor;

// uniform data
layout (location = 0) uniform bool uInstanceRendering;

layout (location = 1) uniform mat4 uModelViewMatrix;
layout (location = 2) uniform mat4 uProjectionMatrix;
layout (location = 3) uniform mat3 uNormalMatrix;

layout (location = 4) uniform vec2 uTexOffset0;
layout (location = 5) uniform vec2 uTexOffset1;

void main(void)
{
    vec4 mvPosition;

    if (uInstanceRendering)
    {
        mvPosition = uModelViewMatrix * InstanceTransform * vec4(VertexPosition, 1.0);
    }
    else
    {
        mvPosition = uModelViewMatrix * vec4(VertexPosition, 1.0);
    }

    vTexSkyboxCoord = VertexPosition; // for skybox rendering

    const float atlasRows = 6.0f;
    vTexCoord0 = (VertexTexCoord / atlasRows) + uTexOffset0;
    vTexCoord1 = (VertexTexCoord / atlasRows) + uTexOffset1;

    vPosition = mvPosition.xyz;

    vNormal = normalize(uNormalMatrix * VertexNormal);

    vClampColor = clamp(VertexPosition, 0.0, 1.0);

    gl_Position = uProjectionMatrix * mvPosition;

#ifdef GL_ES
    gl_PointSize = 10.0f;
#endif
}

在 C++ 端和 GLSL 端都乏味地使用 cmets 之后，我已将错误定位到这行代码：

mvPosition = uModelViewMatrix * InstanceTransform * vec4(VertexPosition, 1.0);

如果我将其注释掉，程序将编译，但它无法执行 glDraw*Instaced 调用而不会出现大量与 gpu 相关的错误（如下所示来自 logcat）。

10-18 15:58:42.504 29196-29238/package W/Adreno-GSL: <gsl_ldd_control:408>: ioctl fd 49 code 0xc02c093d (IOCTL_KGSL_SUBMIT_COMMANDS) failed: errno 35 Resource deadlock would occur
10-18 15:58:42.504 29196-29238/package W/Adreno-GSL: <log_gpu_snapshot:323>: panel.gpuSnapshotPath is not set.not generating user snapshot
10-18 15:58:42.504 29196-29238/packageW/Adreno-GSL: <gsl_ldd_control:408>: ioctl fd 49 code 0xc02c093d (IOCTL_KGSL_SUBMIT_COMMANDS) failed: errno 35 Resource deadlock would occur
10-18 15:58:42.504 29196-29238/packageW/Adreno-GSL: <log_gpu_snapshot:323>: panel.gpuSnapshotPath is not set.not generating user snapshot
10-18 15:58:42.504 29196-29238/packageW/Adreno-GSL: <gsl_ldd_control:408>: ioctl fd 49 code 0xc02c093d (IOCTL_KGSL_SUBMIT_COMMANDS) failed: errno 35 Resource deadlock would occur
10-18 15:58:42.504 29196-29238/packageW/Adreno-GSL: <log_gpu_snapshot:323>: panel.gpuSnapshotPath is not set.not generating user snapshot
10-18 15:58:42.504 29196-29238/packageW/Adreno-GSL: <gsl_ldd_control:408>: ioctl fd 49 code 0xc02c093d (IOCTL_KGSL_SUBMIT_COMMANDS) failed: errno 35 Resource deadlock would occur
10-18 15:58:42.504 29196-29238/packageW/Adreno-GSL: <log_gpu_snapshot:323>: panel.gpuSnapshotPath is not set.not generating user snapshot
10-18 15:58:42.504 29196-29238/packageW/Adreno-GSL: <gsl_ldd_control:408>: ioctl fd 49 code 0xc02c093d (IOCTL_KGSL_SUBMIT_COMMANDS) failed: errno 35 Resource deadlock would occur
10-18 15:58:42.504 29196-29238/packageW/Adreno-GSL: <log_gpu_snapshot:323>: panel.gpuSnapshotPath is not set.not generating user snapshot
10-18 15:58:42.504 29196-29238/packageW/Adreno-ES20: <finish_current_fbo_rendering:315>: GL_OUT_OF_MEMORY

我做了一个简单的例子来简单地测试实例渲染，同样的问题在 OpenGL ES 3 中弹出（仍然使用 SDL）。

#version 300 es
precision mediump float;

// attribute data
layout (location = 0) in vec3 aVertexPosition;
layout (location = 1) in vec2 aVertexTexCoord;
layout (location = 2) in vec3 aVertexNormal;
layout (location = 3) in mat4 aInstanceTransform;

// varying data
out vec3 vPosition;
out vec2 vTexCoord;
out vec3 vNormal;

// uniform data
uniform mat4 uModelViewMatrix;
uniform mat4 uProjectionMatrix;
uniform mat3 uNormalMatrix;

void main(void)
{
    vec4 mvTransform = uModelViewMatrix * aInstanceTransform * vec4(aVertexPosition, 1.0);

    vTexCoord = aVertexTexCoord;

    vPosition = mvTransform.xyz;

    vNormal = normalize(uNormalMatrix * aVertexNormal);

    gl_Position = uProjectionMatrix * mvTransform;
}

这里是我设置顶点数据的地方：

glBindBuffer(GL_ARRAY_BUFFER, mVBO_InstanceData);
glBufferData(GL_ARRAY_BUFFER, instanceData.size() * sizeof(glm::mat4), instanceData.data(), GL_STATIC_DRAW);

glEnableVertexAttribArray(3);
glVertexAttribPointer(3, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), reinterpret_cast<GLvoid*>(0));
glVertexAttribDivisor(3, 1); // increment instance data by 1 each iteration

glEnableVertexAttribArray(4);
glVertexAttribPointer(4, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), reinterpret_cast<GLvoid*>(sizeof(glm::vec4)));
glVertexAttribDivisor(4, 1);

glEnableVertexAttribArray(5);
glVertexAttribPointer(5, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), reinterpret_cast<GLvoid*>(2 * sizeof(glm::vec4)));
glVertexAttribDivisor(5, 1);

glEnableVertexAttribArray(6);
glVertexAttribPointer(6, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), reinterpret_cast<GLvoid*>(3 * sizeof(glm::vec4)));
glVertexAttribDivisor(6, 1);

Answer 1

您的某些location 限定符与300 es 着色器版本不兼容。您的顶点着色器包含以下定义：

layout (location = 0) out vec3 vPosition;
...

GLSL ES 3.00 规范说：

顶点着色器不能有输出布局限定符。

此限制仅在 3.10 版本中解除，相应的措辞已更改为：

顶点和片段着色器允许在输出变量声明中使用位置布局限定符。

几乎同样的事情也适用于你使用的制服：

layout (location = 0) uniform bool uInstanceRendering;
...

此外，着色器版本 3.00 不允许在制服上使用 layout 限定符：

布局限定符可用于统一块，但不能用于非块统一声明。

同样，此选项是在 3.10 版中添加的。

Answer 2

我发现在顶点着色器中仅使用“glBindAttribLocation”而不是布局限定符可以解决问题。我什至使用了与布局限定符相同的编号方案。我想知道我是否可以用 4 个 vec4 设置实例数据？我猜 mat4 在我的移动设备上抛出了编号方案？