如何在OpenGL纹理中更改单个纹理 [英] How to change single texel in OpenGL texture

问题描述

我想更改给定位置的OpenGL纹理中的某些纹理像素.有人可以帮我这个忙吗?

I want to change the some texels in a OpenGL texture for a given location. Can anyone help me with this pls ?

这是我想要的功能，

void ChangeTexelColor(int x, int y, GLuint id, int texW, int texH, GLenum format)
{
   //What is here ?     
}

这将用于维护我的游戏的小地图(如果有人对维护动态map-texture-有更好的主意).顺便说一句，这必须做得很快.谢谢.

This will use to maintain the minimap of my game (if anyone have a better idea of maintaining a dynamic map-texture-). Btw, this must done fast. Thanks.

推荐答案

OpenGL具有glTexSubImage2D功能，正是您想要的功能.

OpenGL has the glTexSubImage2D function, which is exactly for your purpose.

这是一个可更改一个纹理像素颜色的函数:

Here's a functions that changes the color of one texel:

void changeTexelColor(GLuint id, GLint x, GLint y, uint8_t r, uint8_t g, uint8_t b, uint8_t a) {
    uint8_t data[4];
    data[0] = r;
    data[1] = g;
    data[2] = b;
    data[3] = a;
    glBindTexture(GL_TEXTURE_2D, id);
    glTexSubImage2D(GL_TEXTURE_2D,
                    0,
                    x,
                    y,
                    1,
                    1,
                    GL_RGBA,
                    GL_UNSIGNED_BYTE,
                    data);
}

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