OpenGL渲染到纹理
如何使用framebuffer对象渲染纹理并将该纹理用作我的着色器的输入。
我需要执行此操作以进行可编程混合。
我可以单独创建一个FBO和纹理，但不能渲染到该纹理并附加我的帧缓冲区对象。
我需要渲染到纹理，因为我想将此纹理传递给我的着色器，以便我能够编写自己的可编程混合方程。
#include <glad/glad.h>
#include <GLFW\glfw3.h>
#include <iostream>
#include "shader.h"
#include "std_image.h"
using namespace std;
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
int main()
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
if (window == NULL)
{
cout << "Failed to create GLFW window" <<endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
cout << "Failed to initialize GLAD" <<endl;
return -1;
}
glViewport(0, 0, 800, 600);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
///////////////////////////////////////////////////////////////////////////////////
Shader ourShader("Shader.vs", "Shader.fs");
Shader ourShader2("Shader.vs", "Shader2.fs");
unsigned int FBO;
glGenFramebuffers(1, &FBO);
glBindFramebuffer(GL_FRAMEBUFFER, FBO);
unsigned int attachment_index_color_texture = 0;
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + attachment_index_color_texture, GL_UNSIGNED_BYTE, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0); //unbind framebuffer
float vertices[] = {
// positions // colors // texture coords
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top right
0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, // bottom right
-0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, // bottom left
-0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f // top left
};
unsigned int indices[] = {
0, 1, 3, // first triangle
1, 2, 3 // second triangle
};
float vertices2[] = {
// positions // colors // texture coords
0.75f, 0.75f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, // top right
0.75f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // bottom right
0.0f, 0.0f, 0.0f, 0.0f,1.0f, 0.0f, 0.0f, 0.0f, // bottom left
0.0f, 0.75f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f // top left
};
unsigned int indices2[] = {
0, 1, 2, // first triangle
0, 2, 3 // second triangle
};
unsigned int VBO[2],VAO[2],EBO[2];
glGenVertexArrays(2, VAO);
glGenBuffers(2, VBO);
glGenBuffers(2, EBO);
glBindVertexArray(VAO[0]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO[0]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
glBindVertexArray(0);
glBindVertexArray(VAO[1]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices2), vertices2, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO[1]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices2), indices2, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ONE);
while (!glfwWindowShouldClose(window))
{
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
ourShader.use();
glBindVertexArray(VAO[0]);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
ourShader2.use();
glBindVertexArray(VAO[1]);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glfwSwapBuffers(window);
glfwPollEvents();
}
/*glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glDeleteBuffers(1, &EBO);*/
glfwTerminate();
return 0;
}
编辑1：
我现在将我的纹理附加到fbo，也在我的textrue上渲染，如下所示：
while (!glfwWindowShouldClose(window))
{
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
ourShader.use();
glBindVertexArray(VAO[0]);
unsigned int FBO, color, depth;
glGenFramebuffers(1, &FBO);
glGenTextures(1, &color);
glBindFramebuffer(GL_FRAMEBUFFER, FBO);
glBindTexture(GL_TEXTURE_2D, color);
glGenRenderbuffers(1, &depth);
glTexImage2D(GL_TEXTURE_2D,
0,
GL_RGBA,
800, 600,
0,
GL_RGBA,
GL_UNSIGNED_BYTE,
NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, color, 0);
GLenum DrawBuffers[1] = { GL_COLOR_ATTACHMENT0 };
glDrawBuffers(1, DrawBuffers); // "1" is the size of DrawBuffers
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
return false;
glBindFramebuffer(GL_FRAMEBUFFER, FBO);
glViewport(0, 0, 800, 600); // Render on the whole framebuffer, complete from the lower left corner to the upper right
glBindFramebuffer(GL_FRAMEBUFFER, 0);
ourShader2.use();
glBindVertexArray(VAO[1]);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glfwSwapBuffers(window);
glfwPollEvents();
}
剩下的一个问题是我如何通过我的纹理＆＃34;颜色＆＃34;在我的着色器中。
感谢您的帮助
EDIT2：
我附上了我的整个代码，请你检查我为什么屏幕上没有任何内容。
main.cpp中：
#include <glad/glad.h>
#include <GLFW\glfw3.h>
#include <iostream>
#include "shader.h"
#include "std_image.h"
using namespace std;
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
int main()
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
if (window == NULL)
{
cout << "Failed to create GLFW window" <<endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
cout << "Failed to initialize GLAD" <<endl;
return -1;
}
glViewport(0, 0, 800, 600);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
///////////////////////////////////////////////////////////////////////////////////
Shader ourShader("Shader.vs", "Shader.fs");
Shader ourShader2("Shader.vs", "Shader2.fs");
//glBindFramebuffer(GL_FRAMEBUFFER, 0); //unbind framebuffer
float vertices[] = {
// positions // colors // texture coords
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top right
0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, // bottom right
-0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, // bottom left
-0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f // top left
};
unsigned int indices[] = {
0, 1, 3, // first triangle
1, 2, 3 // second triangle
};
float vertices2[] = {
// positions // colors // texture coords
0.75f, 0.75f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, // top right
0.75f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // bottom right
0.0f, 0.0f, 0.0f, 0.0f,1.0f, 0.0f, 0.0f, 0.0f, // bottom left
0.0f, 0.75f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f // top left
};
unsigned int indices2[] = {
0, 1, 2, // first triangle
0, 2, 3 // second triangle
};
unsigned int VBO[2],VAO[2],EBO[2];
glGenVertexArrays(2, VAO);
glGenBuffers(2, VBO);
glGenBuffers(2, EBO);
glBindVertexArray(VAO[0]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO[0]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
glBindVertexArray(0);
glBindVertexArray(VAO[1]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices2), vertices2, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO[1]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices2), indices2, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ONE);
while (!glfwWindowShouldClose(window))
{
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
ourShader.use();
glBindVertexArray(VAO[0]);
unsigned int FBO, color, depth;
glGenFramebuffers(1, &FBO);
glGenTextures(1, &color);
glBindFramebuffer(GL_FRAMEBUFFER, FBO);
glBindTexture(GL_TEXTURE_2D, color);
glGenRenderbuffers(1, &depth);
glTexImage2D(GL_TEXTURE_2D,
0,
GL_RGBA,
800, 600,
0,
GL_RGBA,
GL_UNSIGNED_BYTE,
NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, color, 0);
unsigned int decalTexLocation;
decalTexLocation = glGetUniformLocation(ourShader.ID, "DecalTex");
glUniform1i(decalTexLocation, 0);
glActiveTexture(GL_TEXTURE0 + 0);
glBindTexture(GL_TEXTURE_2D, color);
GLenum DrawBuffers[2] = { GL_COLOR_ATTACHMENT0 };
glDrawBuffers(1, &DrawBuffers[0]); // "1" is the size of DrawBuffers
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
return false;
glViewport(0, 0, 800, 600); // Render on the whole framebuffer, complete from the lower left corner to the upper right
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
ourShader2.use();
glBindVertexArray(VAO[1]);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glfwSwapBuffers(window);
glfwPollEvents();
}
/*glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glDeleteBuffers(1, &EBO);*/
glfwTerminate();
return 0;
}
Fragment Shader1：
#version 330 core
out vec4 FragColor;
in vec3 ourColor;
void main()
{
// vec4 dst = getCurrentColorAtOutputFragmentPosition();
FragColor = vec4(ourColor, 1.0);
}
Fragment Shader2：
#version 330 core
out vec4 FragColor;
uniform sampler2D DecalTex;
in vec3 ourColor;
void main()
{
vec2 coords = gl_TexCoord[0].xy;
vec3 normalColor = texture2D(DecalTex, coords).rgb; //original color
FragColor = vec4(normalColor.x,normalColor.y,normalColor.z, 1.0);
}
顶点着色器：
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;
out vec3 ourColor;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(aPos, 1.0);
ourColor = aColor;
TexCoord = aTexCoord;
}
编辑3：
在下面的代码中，我渲染了2个矩形，一个是使用FBO（帧缓冲区对象）的纹理，另一个是在屏幕上。
我可以在屏幕上渲染。
我写了2个片段着色器和2个顶点着色器。
一对片段和顶点着色器用于渲染纹理，另一对用于在屏幕上渲染。
我的主要档案：
#include <glad/glad.h>
#include <GLFW\glfw3.h>
#include <iostream>
#include "shader.h"
#include "std_image.h"
using namespace std;
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
glViewport(0, 0, width, height);
}
int main()
{
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
if (window == NULL)
{
cout << "Failed to create GLFW window" <<endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
cout << "Failed to initialize GLAD" <<endl;
return -1;
}
glViewport(0, 0, 800, 600);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
///////////////////////////////////////////////////////////////////////////////////
Shader ourShader("Shader.vs", "Shader.fs");
Shader ourShader2("Shader2.vs", "Shader2.fs");
//glBindFramebuffer(GL_FRAMEBUFFER, 0); //unbind framebuffer
float vertices[] = {
// positions // colors // texture coords
0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top right
0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, // bottom right
-0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, // bottom left
-0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f // top left
};
unsigned int indices[] = {
0, 1, 3, // first triangle
1, 2, 3 // second triangle
};
float vertices2[] = {
// positions // colors // texture coords
1.0, 1.0, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, // top right
1.0, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // bottom right
0.0f, 0.0f, 0.0f, 0.0f,1.0f, 0.0f, 0.0f, 0.0f, // bottom left
0.0f, 1.0, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f // top left
};
unsigned int indices2[] = {
0, 1, 2, // first triangle
0, 2, 3 // second triangle
};
unsigned int VBO[2],VAO[2],EBO[2];
glGenVertexArrays(2, VAO);
glGenBuffers(2, VBO);
glGenBuffers(2, EBO);
glBindVertexArray(VAO[0]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO[0]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
glBindVertexArray(0);
glBindVertexArray(VAO[1]);
glBindBuffer(GL_ARRAY_BUFFER, VBO[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices2), vertices2, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO[1]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices2), indices2, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
/*glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ONE)*/;
unsigned int color;
glGenTextures(1, &color);
glBindTexture(GL_TEXTURE_2D, color);
glTexImage2D(GL_TEXTURE_2D,
0,
GL_RGBA,
800, 600,
0,
GL_RGBA,
GL_UNSIGNED_BYTE,
NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
unsigned int FBO;
glGenFramebuffers(1, &FBO);
glBindFramebuffer(GL_FRAMEBUFFER, FBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);
while (!glfwWindowShouldClose(window))
{
ourShader.use();
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glBindVertexArray(VAO[0]);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
ourShader2.use();
int texturehandle = glGetUniformLocation(ourShader.ID, "DecalTex");
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, color);
glUniform1i(texturehandle, 0);
glBindVertexArray(VAO[1]);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
return 0;
}
Veretx Shader 1：
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;
out vec3 ourColor;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(aPos, 1.0);
ourColor = aColor;
TexCoord = aTexCoord;
}
片段着色器1
#version 330 core
out vec4 FragColor;
in vec3 ourColor;
void main()
{
// vec4 dst = getCurrentColorAtOutputFragmentPosition();
FragColor = vec4(ourColor, 1.0);
}
顶点着色器2
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;
out vec3 ourColor;
out vec2 myUV;
void main()
{
gl_Position = vec4(aPos, 1.0);
ourColor = aColor;
myUV = vec2(aPos.x,aPos.y);
}
片段着色器2
#version 330 core
out vec4 FragColor;
uniform sampler2D DecalTex;
in vec3 ourColor;
in vec2 UV;
void main()
{
vec2 outUV = vec2(0.26,0.26);
vec4 myFragColor = texture2D(DecalTex,outUV);
//vec4 myFragColor = texture2D(DecalTex,UV);
//FragColor = vec4(ourColor,1.0);
vec4 tempFragColor = vec4(ourColor, 1.0);
//FragColor = myFragColor;
FragColor = myFragColor + tempFragColor;
//FragColor = (1.0,1.0,1.0,1.0);//tempFragColor;
}
这里的问题是，当我使用该行时：
vec4 myFragColor = texture2D(DecalTex,UV);
我无法在myFragColor中获取任何值，因此会发生正常渲染。
但如果我改为
vec2 outUV = vec2(0.26,0.26);
vec4 myFragColor = texture2D(DecalTex,outUV);
我能够获得目标像素的值，因此根据我的需要进行渲染。
请告诉我为什么我不能来：
vec4 myFragColor = texture2D(DecalTex,UV);
编辑4
现在我可以访问目标像素，但只剩下1个问题：
第一个矩形坐标（-0.5，-0.5）＆lt; -----＆gt; （0.5,0.5）
第二矩形坐标（0,0）＆lt; ----＆gt; （1,1）
交叉区域（0,0）＆lt; ----＆gt; （0.5,0.5）--------＆gt;这应该是黄色（红色+绿色）
但是面积（0.26,0.26）＆lt; -------＆gt; （0.74,0.74）------＆gt;这是黄色的，任何原因都很奇怪..？
最新片段着色器：
#version 330 core
out vec4 FragColor;
uniform sampler2D DecalTex;
in vec3 ourColor;
in vec2 myUV;
void main()
{
vec4 myFragColor = texture2D(DecalTex,myUV);
FragColor = vec4(ourColor,1.0);
vec4 tempFragColor = vec4(ourColor, 1.0);
FragColor = myFragColor + tempFragColor;
}
预期结果：
2 个答案:
答案 0 :(得分：2)
现在你应该有一个你的纹理ID和＃34;颜色＆＃34;已经填满，所以你可以绑定并将其传递给着色器。
int texturehandle = glGetUniformLocation(program, "MaTextureInShader");
glActiveTexture(GLES20.GL_TEXTURE0);
glBindTexture(GLES20.GL_TEXTURE_2D, color);
glUniform1i(textureHandle, 0);
如果要将其存储在数组中
glBindTexture(GLES20.GL_TEXTURE_2D, color);
GL::glGetTexImage(GL::GL_TEXTURE_2D, 0, GL_RGBA, GL_FLOAT, myArray);
答案 1 :(得分：2)
编译片段着色器2时，会出现这样的错误消息（取决于图形驱动程序）;
0（12）：错误C7616：版本140之后删除了全局变量
gl_TexCoord
这意味着您无法将gl_TexCoord与#version 330 core结合使用。
您已经为顶点着色器中的纹理坐标定义了变量out变量。
out vec2 myUV;
在片段着色器中定义相应的in变量并使用它，而不是gl_TexCoord：
#version 330 core
out vec4 FragColor;
uniform sampler2D DecalTex;
in vec3 ourColor;
in vec2 myUV;
void main()
{
vec4 myFragColor = texture2D(DecalTex,myUV);
FragColor = myFragColor;
}
答案的延伸：
要正确链接着色器程序并使其正常工作，变量out变量的名称必须与变量in变量的名称完全匹配。
这意味着这是顶点着色器中名为myUV的纹理坐标的输出变量：
out vec2 myUV;
片段着色器中相应的输入变量也必须命名为myUV：
in vec2 myUV;
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