我正在学习 OpenGL 3.3，使用一些教程 (http://opengl-tutorial.org)。在我正在使用的教程中，有一个顶点着色器，它执行以下操作：
教程着色器源
#version 330 core
// Input vertex data, different for all executions of this shader.
layout(location = 0) in vec3 vertexPosition_modelspace;
// Values that stay constant for the whole mesh.
uniform mat4 MVP;
void main(){
// Output position of the vertex, in clip space : MVP * position
gl_Position = MVP * vec4(vertexPosition_modelspace,1);
}
然而，当我尝试在我的应用程序中模拟相同的行为时，我得到以下信息：
error: implicit cast from "vec4" to "vec3".
看到这个后，我不确定是不是因为我使用的是 4.2 版本的着色器而不是 3.3，所以更改了所有内容以匹配作者一直使用的内容，之后仍然收到相同的错误。
所以，我改变了我的着色器来做到这一点：
我的（最新）来源
#version 330 core
layout(location = 0) in vec3 vertexPosition_modelspace;
uniform mat4 MVP;
void main()
{
vec4 a = vec4(vertexPosition_modelspace, 1);
gl_Position.xyz = MVP * a;
}
当然，这仍然会产生相同的错误。
有谁知道为什么会这样，以及对此的解决方案可能是什么？我不确定它是否是我的调用代码（我已经发布了，以防万一）。
调用代码
static const GLfloat T_VERTEX_BUF_DATA[] =
{
// x, y z
-1.0f, -1.0f, 0.0f,
1.0f, -1.0f, 0.0f,
0.0f, 1.0f, 0.0f
};
static const GLushort T_ELEMENT_BUF_DATA[] =
{ 0, 1, 2 };
void TriangleDemo::Run(void)
{
glClear(GL_COLOR_BUFFER_BIT);
GLuint matrixID = glGetUniformLocation(mProgramID, "MVP");
glUseProgram(mProgramID);
glUniformMatrix4fv(matrixID, 1, GL_FALSE, &mMVP[0][0]); // This sends our transformation to the MVP uniform matrix, in the currently bound vertex shader
const GLuint vertexShaderID = 0;
glEnableVertexAttribArray(vertexShaderID);
glBindBuffer(GL_ARRAY_BUFFER, mVertexBuffer);
glVertexAttribPointer(
vertexShaderID, // Specify the ID of the shader to point to (in this case, the shader is built in to GL, which will just produce a white triangle)
3, // Specify the number of indices per vertex in the vertex buffer
GL_FLOAT, // Type of value the vertex buffer is holding as data
GL_FALSE, // Normalized?
0, // Amount of stride
(void*)0 ); // Offset within the array buffer
glDrawArrays(GL_TRIANGLES, 0, 3); //0 => start index of the buffer, 3 => number of vertices
glDisableVertexAttribArray(vertexShaderID);
}
void TriangleDemo::Initialize(void)
{
glGenVertexArrays(1, &mVertexArrayID);
glBindVertexArray(mVertexArrayID);
glGenBuffers(1, &mVertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, mVertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(T_VERTEX_BUF_DATA), T_VERTEX_BUF_DATA, GL_STATIC_DRAW );
mProgramID = LoadShaders("v_Triangle", "f_Triangle");
glm::mat4 projection = glm::perspective(45.0f, 4.0f / 3.0f, 0.1f, 100.0f); // field of view, aspect ratio (4:3), 0.1 units near, to 100 units far
glm::mat4 view = glm::lookAt(
glm::vec3(4, 3, 3), // Camera is at (4, 3, 3) in world space
glm::vec3(0, 0, 0), // and looks at the origin
glm::vec3(0, 1, 0) // this is the up vector - the head of the camera is facing upwards. We'd use (0, -1, 0) to look upside down
);
glm::mat4 model = glm::mat4(1.0f); // set model matrix to identity matrix, meaning the model will be at the origin
mMVP = projection * view * model;
}
笔记
- 我在 Visual Studio 2012
- 我正在使用Shader Maker进行 GLSL 编辑