我有一个代码,最初有一个着色器(ourShader),一个VAO和一个VBO。它将使用模板测试渲染具有纹理立方体的场景以及它在地面上的反射。现在,我想添加一个帧缓冲器进行后期处理,所以我需要第二个着色器。我添加了第二个着色器(screenShader)和第二个VBO。我还没有在我的绘图中使用它们,但是我添加它们的简单事实使得我的代码渲染了一个黑色的红色三角形,而不是通常的场景。OpenGL:第二个VBO破坏第一个VBO
我的代码如下所示:
Shader ourShader(string("core.vs"), string("core.frag")); // shader class creating a shader program from vertex shader and fragment shader source files.
Shader screenShader(string("core2.vs"), string("core2.frag"));
// Setting up attributes, VAO, VBO
GLuint VAO;
array<GLuint, 2> VBO;
glGenVertexArrays(1, &VAO);
glGenBuffers(2, &VBO[0]);
glBindVertexArray(VAO);
// Data for first shader and first VBO
glBindBuffer(GL_ARRAY_BUFFER, VBO[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(verticesCube), verticesCube, GL_STATIC_DRAW);
GLint posAttribLoc = glGetAttribLocation(ourShader.Program, "position");
glVertexAttribPointer(posAttribLoc, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0); // specify (to the active VAO) how to retrieve the values for the attribute "position" from the data stored ("vertices" here) on the active VBO (GPU)
glEnableVertexAttribArray(posAttribLoc); // enable attribute for rendering
GLint colAttribLoc = glGetAttribLocation(ourShader.Program, "color");
glVertexAttribPointer(colAttribLoc, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(colAttribLoc);
GLint texAttribLoc = glGetAttribLocation(ourShader.Program, "texCoord");
glVertexAttribPointer(texAttribLoc, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(texAttribLoc);
// ##### PART GIVING A WEIRD RESULT #####
// Data for second shader and second VBO
glBindBuffer(GL_ARRAY_BUFFER, VBO[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(verticesRectangle), verticesRectangle, GL_STATIC_DRAW);
GLint posAttribLoc2 = glGetAttribLocation(screenShader.Program, "position");
glVertexAttribPointer(posAttribLoc2, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (GLvoid*)0); // specify (to the active VAO) how to retrieve the values for the attribute "position" from the data stored ("vertices" here) on the active VBO (GPU)
glEnableVertexAttribArray(posAttribLoc2); // enable attribute for rendering
GLint texAttribLoc2 = glGetAttribLocation(screenShader.Program, "texCoord");
glVertexAttribPointer(texAttribLoc2, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (GLvoid*)(2 * sizeof(GLfloat)));
glEnableVertexAttribArray(texAttribLoc2);
// ##### END #####
// Setting up texture that will be used for the first shader
GLuint texture;
int width, height;
glGenTextures(1, &texture);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture); // makes "texture" the current texture and attaches it to texture unit 0
// Set the wrapping
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// Set the filtering
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
unsigned char* image = SOIL_load_image("res/images/image1.jpg", &width, &height, 0, SOIL_LOAD_RGBA);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
SOIL_free_image_data(image);
// Unbind VBO, texture before main loop
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glfwSwapInterval(1);
glfwSetKeyCallback(window, Input::keyCallback); // Input is a singleton class handling inputs. It works well.
glfwSetCursorPosCallback(window, Input::mouseCallback);
glfwSetScrollCallback(window, Input::scrollCallback);
while (glfwWindowShouldClose(window) == GLFW_FALSE) {
// MAIN LOOP
// ...
}
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(2, &VBO[0]);
主循环并不重要,我认为。我想说的是,如果我删除处理第二个VBO的几条线,那么场景呈现良好。否则,我会得到一个奇怪的三角形。
而我的两个着色器将这些源文件用于各自的顶点着色器和片段着色器。顺便说一句,我没有从我的着色器编译错误。
core.vs:
#version 330 core
in vec3 position;
in vec2 texCoord;
in vec3 color;
out vec2 TexCoord;
out vec3 Color;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection*view*model*vec4(position, 1.0);
TexCoord = vec2(texCoord.x, 1.0 - texCoord.y);
Color = color;
}
core.frag:
#version 330 core
in vec2 TexCoord;
in vec3 Color;
out vec4 outColor;
uniform sampler2D ourTexture0;
void main()
{
outColor = vec4(Color, 1)*texture(ourTexture0, TexCoord);
}
core2.vs:
#version 330 core
in vec2 position;
in vec2 texCoord;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(position, 0.0, 1.0);
TexCoord = texCoord;
}
core2.frag:
#version 330 core
in vec2 TexCoord;
out vec4 outColor;
uniform sampler2D texFramebuffer;
void main()
{
outColor = texture(texFramebuffer, TexCoord);
}
个顶点看起来像这样(但只有这样看他们是很重要的):
GLfloat verticesRectangle[] = {
// position // texture coordinates
-0.5f, -0.5f, 0.0f, 0.0f,
0.5f, -0.5f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.0f, 1.0f,
0.5f, 0.5f, 1.0f, 1.0f
};
GLfloat verticesCube[] = {
// position // color // texture coordinates
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-1.0f, -0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, // reflection surface // not a part of the cube itself
-1.0f, -0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f,
1.0f, -0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f,
1.0f, -0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f,
-1.0f, -0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f,
1.0f, -0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f
};
我已经看过Binding a second vertex buffer seems to spoil my first vertex buffer, OpenGL OES ios 5.1而是因为他没有正确的使用他的VAO的人有这个问题。
什么是使用VAOs如果你只有一个点? – Frank