c++ - 我的 OpenGL 程序的着色器不影响几何图形或为多边形着色

Question

我有一个顶点和片段着色器，不久前还运行良好，但我试图实现骨骼动画，但沿线的某个地方出了问题。我什至不再使用我的自定义函数，只是设置了一个简单的“绘制三角形并为其着色”代码块，但它不起作用。

绘图代码:

GLfloat vertices[] = {
    0.5f,  0.5f, 0.0f,  // Top Right
    0.5f, -0.5f, 0.0f,  // Bottom Right
    -0.5f, -0.5f, 0.0f,  // Bottom Left
    -0.5f,  0.5f, 0.0f   // Top Left 
};
GLuint indices[] = {  // Note that we start from 0!
    0, 1, 3,  // First Triangle
    1, 2, 3   // Second Triangle
};
GLuint VBO, VAO, EBO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &EBO);
// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
glBindVertexArray(VAO);

glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);

glBindBuffer(GL_ARRAY_BUFFER, 0); // Note that this is allowed, the call to glVertexAttribPointer registered VBO as the currently bound vertex buffer object so afterwards we can safely unbind

glBindVertexArray(0); 

while (!win.windowShouldClose) {

    win.clearScreen(glm::vec4(1.0f,1.0f,1.0f,1.0f));
    newShader.Use();
    GLint mvpLoc = glGetUniformLocation(newShader.Program, "MVP");
    glUniformMatrix4fv(mvpLoc, 1, GL_FALSE, glm::value_ptr(camera.proj * camera.view));
    glBindVertexArray(VAO);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
    glBindVertexArray(0);

    win.display();

}

顶点着色器:

#version 430
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoords;

out vec2 TexCoords;
out vec3 ourColor;

uniform mat4 MVP;

void main()
{
    gl_Position =  MVP * vec4(position,1.0f);
    TexCoords = texCoords;
    ourColor = vec3(1.0f, 0.0f, 1.0f);
}

片段着色器:

#version 430

in vec2 TexCoords;
in vec3 ourColor;
out vec4 color;
uniform sampler2D texture_diffuse1;
void main() {
  color = vec4(ourColor,1.0f);
}

我花了好几天的时间来解决这个问题，但我离找到解决方案还差得很远。我认为这是我发送到着色器的数据的问题，但即使如图所示使片段的输出为常量，三角形仍然是黑色的并且根本不受顶点着色器的影响，就好像它们正在运行一样直接从 NDC 到屏幕空间。

Answer 1

因为你没有显示 camera 属性，我怀疑你的投影和 View 矩阵有任何问题(即，MVP 矩阵可能会将对象转换到屏幕之外)。我刚刚在我的电脑上用 glfw 库测试了你的程序，我的测试结果表明你的代码没有问题。也就是说，“我认为这是我发送给着色器的数据的问题”没有问题

尝试移除顶点着色器的 MVP 矩阵:

#version 430
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoords;

out vec2 TexCoords;
out vec3 ourColor;

uniform mat4 MVP;

void main()
{
    // Remove MVP matrix
    gl_Position = vec4(position,1.0f);
    TexCoords   = texCoords;
    ourColor    = vec3(1.0f, 0.0f, 1.0f);
}