[英]Texture mapping results in solid color of 1 pixel from texture
事先,对于很多已发布的代码,我们深表歉意。 我将尝试变得尽可能简单。
我的纹理是bmp格式的4x4纹理图像(如果有人对此感兴趣-> )。 作为映射的结果,我得到了左上像素的颜色(0.0,1.0)(我检查了一下,它始终是左上像素的颜色),而我的三角形颜色得到的是该像素的颜色,即白色。
我尝试在
GL_TEXTURE_MAG_FILTER
GL_NEAREST
更改为GL_LINEAR
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
我得到右下像素(1.0,0.0),这是某种绿色: 我正在使用stb_image加载纹理。 所以在我的Texture.cpp中 :
Texture::Texture(const std::string& fileName)
{
int width, height, numComponents;
unsigned char* imageData = stbi_load(fileName.c_str(), &width, &height, &numComponents, 4);
if (imageData == NULL)
{
std::cerr << "Error: Texture load failed for texture: " << fileName << std::endl;
}
glEnable(GL_TEXTURE_2D);
glGenTextures(1, &_texture);
glBindTexture(GL_TEXTURE_2D, _texture);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
stbi_image_free(imageData);
}
Texture::~Texture(void)
{
glDeleteTextures(1, &_texture);
}
void Texture::Bind(unsigned int unit)
{
assert(unit >= 0 && unit <= 31);
glActiveTexture(GL_TEXTURE0 + unit);
glBindTexture(GL_TEXTURE_2D, _texture);
}
在我的顶点着色器中 :
#version 150
in vec3 position;
in vec2 texCoord;
out vec2 texCoord0;
void main(void)
{
texCoord0 = texCoord;
gl_Position = vec4(position, 1.0);
}
在我的片段着色器中 :
#version 150
in vec2 textCoord0;
uniform sampler2D texture;
void main(void)
{
gl_FragColor = texture2D(texture, textCoord0);
}
在我的main.cpp中
#include <iostream>
#include <GL/glew.h>
#include "Display.h"
#include "Shader.h"
#include "Mesh.h"
#include "Texture.h"
int main(int argc, char** argv)
{
Display display(800, 600, " ");
display.Clear(0.0f, 0.15f, 0.3f, 1.0f);
Vertex vertices[] = {
Vertex(glm::vec3(-1.0f, -1.0f, 0.0f), glm::vec2(0.0f, 0.0f)),
Vertex(glm::vec3( 0.0f, 1.0f, 0.0f), glm::vec2(0.5f, 1.0f)),
Vertex(glm::vec3( 1.0f, -1.0f, 0.0f), glm::vec2(1.0f, 0.0f))
};
Texture texture("./res/a.bmp");
Shader shader("./res/testShader");
Mesh mesh(vertices, sizeof(vertices) / sizeof(vertices[0]));
while (display.IsClosed() != true)
{
shader.Bind();
texture.Bind(0);
mesh.Draw();
display.Update();
}
return 0;
}
在Mesh.cpp中,我将顶点属性(glm :: vec3 _position和glm :: vec2 _texture)拆分为2个stl向量,并使用2个缓冲区(“ 0”-用于顶点位置,“ 1”-用于纹理):
Mesh::Mesh(Vertex* vertices, unsigned int numVertices, GLenum usage)
{
_drawCount = numVertices;
glGenVertexArrays(1, &_vertexArrayObject);
glBindVertexArray(_vertexArrayObject);
std::vector<glm::vec3> positions;
std::vector<glm::vec2> texCoords;
positions.reserve(numVertices);
texCoords.reserve(numVertices);
for (unsigned int i = 0; i < numVertices; ++i)
{
positions.push_back(*vertices[i].Position());
texCoords.push_back(*vertices[i].TexCoord());
}
glGenBuffers(NUM_BUFFERS, _vertexArrayBuffers);
glBindBuffer(GL_ARRAY_BUFFER, _vertexArrayBuffers[POSITION_VB]);
glBufferData(GL_ARRAY_BUFFER, numVertices * sizeof(positions[0]), positions.data(), usage);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, _vertexArrayBuffers[TEXCOORD_VB]);
glBufferData(GL_ARRAY_BUFFER, numVertices * sizeof(texCoords[0]), texCoords.data(), usage);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, 0);
glBindVertexArray(0);
}
Mesh::~Mesh(void)
{
glDeleteVertexArrays(1, &_vertexArrayObject);
}
void Mesh::Draw(GLenum mode)
{
glBindVertexArray(_vertexArrayObject);
glDrawArrays(mode, 0, _drawCount);
glBindVertexArray(0);
}
在Shader.cpp中,我这样绑定属性:
glBindAttribLocation(_program, 0, "position");
glBindAttribLocation(_program, 1, "texCoord");
- - - - - - - - - - - - - - 编辑 - - - - - - - - - - - ------------将顶点着色器更改为:
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec2 texCoord;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(position, 1.0f);
TexCoord = texCoord;
}
和片段着色器可以:
#version 330 core
in vec2 TexCoord;
out vec4 color;
uniform sampler2D ourTexture;
void main()
{
color = texture(ourTexture, TexCoord);
}
纹理正确映射。
但是我仍然想知道为什么我的第一个解决方案不起作用。
但是我仍然想知道为什么我的第一个解决方案不起作用。
因为你在用
#version 330 core
自版本130
起不推荐使用 texture2D
着色器编译器应该对此进行警告或错误。 通过glGetShaderInfoLog
和glGetProgramInfoLog
检查着色器日志。
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