我想绘制出两个纹理三角形,使用包含屏幕上的坐标和纹理坐标以及具有索引的IBO的VBO。但是我遇到了一个问题。无需使用着色器,无论我如何尝试,我都可以获得两个三角形的正确大小和位置,但无纹理。使用着色器时,我会得到纹理,但是三角形尺寸错误,位置错误,并且没有以任何方式使用纹理坐标。使用VBO/IBO的OpenGL纹理三角形
创建纹理
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexImage2D(GL_TEXTURE_2D, 0, nOfColors, surface->w, surface->h, 0,
texture_format, GL_UNSIGNED_BYTE, surface->pixels);
glBindTexture(GL_TEXTURE_2D, NULL);
灌装VBO和IBO (TileData是有两个尺寸的结构2个阵列)
indices.push_back(0);
indices.push_back(1);
indices.push_back(2);
indices.push_back(0);
indices.push_back(2);
indices.push_back(3);
TileData tile;
tile.texCoord[0] = 0/imageSizeX;
tile.texCoord[1] = 0/imageSizeY;
tile.worldCoord[0] = 0;
tile.worldCoord[1] = 0;
tiles.push_back(tile);
tile.texCoord[0] = (0 + texWidth)/imageSizeX;
tile.texCoord[1] = 0/imageSizeY;
tile.worldCoord[0] = 0 + texWidth;
tile.worldCoord[1] = 0;
tiles.push_back(tile);
tile.texCoord[0] = (0 + texWidth)/imageSizeX;
tile.texCoord[1] = (0 + texHeight)/imageSizeY;
tile.worldCoord[0] = 0 + texWidth;
tile.worldCoord[1] = 0 + texHeight;
tiles.push_back(tile);
tile.texCoord[0] = 0/imageSizeX;
tile.texCoord[1] = (0 + texHeight)/imageSizeY;
tile.worldCoord[0] = 0;
tile.worldCoord[1] = 0 + texHeight;
tiles.push_back(tile);
这使代码给我的世界坐标和纹理坐标:
0, 0 0, 0
16, 0 0.25, 0
16, 16 0.25, 1
0, 16 0, 1
生成我缓冲器
glGenBuffers(1, &vboID);
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glBufferData(GL_ARRAY_BUFFER, tiles.size() * sizeof(TileData), &tiles[0], GL_STATIC_DRAW);
glGenBuffers(1, &iboID);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, iboID);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(GLuint), &indices[0], GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
使用着色器绘制功能
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(camera.x, camera.x + 320, camera.y + 240, camera.y, -1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shaderHandler.programID);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
GLint texLocation = glGetUniformLocation(shaderHandler.programID, "tex");
glUniform1i(texLocation, 0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(CGame::TileData), (GLvoid *)0);
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(CGame::TileData), (GLvoid*)offsetof(CGame::TileData, CGame::TileData::worldCoord));
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, iboID);
glDrawElements(GL_TRIANGLES, indices->size(), GL_UNSIGNED_INT, (GLvoid*)0);
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glBindTexture(GL_TEXTURE_2D, 0);
SDL_GL_SwapWindow(window);
结果 With shader
绘图功能,无需渲染 (上面的代码也可以得到相同的结果,这一个,如果我取消链接shaderprogram)
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glClientActiveTexture(GL_TEXTURE0);
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glVertexPointer(2, GL_FLOAT, sizeof(CGame::TileData), (GLvoid*)0);
glTexCoordPointer(2, GL_FLOAT, sizeof(CGame::TileData), (GLvoid*)offsetof(CGame::TileData, CGame::TileData::worldCoord));
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, iboID);
glDrawElements(GL_TRIANGLES, indices->size(), GL_UNSIGNED_INT, (GLvoid*)0);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);
SDL_GL_SwapWindow(window);
Resulst Without shader
顶点着色器
#version 330
layout(location = 0) in vec2 vert;
layout(location = 1) in vec2 vertTexCoord;
out vec2 fragTexCoord;
void main()
{
fragTexCoord = vertTexCoord;
gl_Position = vec4(vert, 0, 1);
}
片段着色器
#version 330
uniform sampler2D tex;
in vec2 fragTexCoord;
out vec4 finalColor;
void main()
{
finalColor = texture2D(tex, fragTexCoord);
}
在这一点上,我不知道如何继续。我在这里或任何地方找不到任何有助于我的事情。我已经尝试了很多东西,我可能会使用某些不赞成使用的东西,或者做一些不受支持的东西,但我无法弄清楚是什么。
非常感谢!我在使用glEnable时只是在粘贴代码时错过了它。我曾尝试制作一个模型视图/投影矩阵,但我似乎做了错误,或者在测试之前忘了删除glMatrix函数,我不记得了。是的,他们是很奇怪的,出于某种原因,我认为他们是一种跨步争论或某种事情,那么:: worldCoord会让它跳过那部分。但我解决了这个问题,现在它使用了纹理的正确部分!只是投影离开。 – Asddev