c – OpenGL中的Texture Splatting是如何实现的？

我已经阅读了一段时间用于纹理地形的不同技术并遇到了 texture splatting.我发现很多文章讨论如何在OpenGL中做到这一点,但大多数只在理论上讨论它并提供很少甚至没有代码我可以研究.有谁知道/有一些代码在OpenGL中说明了这一点？

为了澄清,我希望能够加载四种不同的纹理,并根据四边形/顶点的高度,将纹理从一个渐变到下一个.

编辑：下面是一些代码,以帮助显示我想知道的内容

#include <windows.h>
#include <SFML/Graphics.hpp>
#include <gl/gl.h>
#include <gl/glu.h>

#define GL_CLAMP_TO_EDGE 0x812F

class Scene {
public:
    void resize( int w,int h ) {
        // OpenGL Reshape
        glViewport( 0,w,h );
        glMatrixMode( GL_PROJECTION );
        glLoadIdentity();
        gluPerspective( 120.0,(GLdouble)w/(GLdouble)h,0.5,500.0 );
        glMatrixMode( GL_MODELVIEW );
    }
};

int main() {

    sf::RenderWindow window(sf::VideoMode(800,600,32),"Test");

    ///Setup the scene,materials,lighting
    Scene scene;
    scene.resize(800,600);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glColorMaterial(GL_FRONT_AND_BACK,GL_EMISSION);
    glEnable(GL_COLOR_MATERIAL);
    glShadeModel(GL_SMOOTH);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_LIGHT0);
    float XL = .5,YL = .1,ZL = 1;
    GLfloat ambientLight[] = { 0.2f,0.2f,1.0f };
    GLfloat diffuseLight[] = { 0.8f,0.8f,0.8,1.0f };
    GLfloat specularLight[] = { 0.5f,0.5f,1.0f };
    GLfloat lightpos[] = {XL,YL,ZL,0.};
    glLightfv(GL_LIGHT0,GL_AMBIENT,ambientLight);
    glLightfv(GL_LIGHT0,GL_DIFFUSE,diffuseLight);
    glLightfv(GL_LIGHT0,GL_SPECULAR,specularLight);
    glLightfv(GL_LIGHT0,GL_POSITION,lightpos);

    ///Test terrain texture splatting

    ///Load the textures
    sf::Image tex1;
    tex1.loadFromFile("texture1.png");
    sf::Image tex2;
    tex2.loadFromFile("texture2.png");

    ///Set the first texture
    GLuint grass;
    glGenTextures(1,&grass);
    glBindTexture(GL_TEXTURE_2D,grass);
    glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_REPLACE);
    glTexParameterf( GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR );
    glTexParameterf( GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR );
    glTexImage2D( GL_TEXTURE_2D,GL_RGBA,tex1.getSize().x,tex1.getSize().y,GL_UNSIGNED_BYTE,(const GLvoid*)tex1.getPixelsPtr() );

    ///Set the second texture
    GLuint dirt;
    glGenTextures(1,&dirt);
    glBindTexture(GL_TEXTURE_2D,dirt);
    glTexEnvf(GL_TEXTURE_ENV,tex2.getSize().x,tex2.getSize().y,(const GLvoid*)tex2.getPixelsPtr() );

    ///Start loop
    while( window.isOpen() ) {
        sf::Event event;
        while( window.pollEvent( event ) ) {
            if( event.type == sf::Event::Closed )
                window.close();
        }

        ///Clear buffer and set camera
        glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluPerspective(50.0,1.0,50);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        gluLookAt(1,1,0);

        ///Begin rendering quad             
        glEnable(GL_TEXTURE_2D);
        glBindTexture(GL_TEXTURE_2D,grass);
        ///I know that around here I should enable blending in order to get my two textures to mix,but I am not certain
        glBegin(GL_QUADS);

            glTexCoord2f(0,0);
            glVertex3f(-0.5,-0.5,0.0);

            glTexCoord2f(1,1);
            glVertex3f(0.5,0.0);

            glTexCoord2f(0,0.0);
        glEnd();

        ///Reset env settings for SFML
        glTexEnvf(GL_TEXTURE_ENV,GL_MODULATE);

        window.display();
    }
    return 1;
}