/* Demo of texture mapping onto a triangle

Implemented Fall 2003
Scott D. Anderson
*/

#include <stdio.h>
#include <stdlib.h>                // for exit
#include <tw.h>

void textureInit(char* imgfile) {
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    twPPM_Tex2D(imgfile,true);
}


void display(void) {
    twDisplayInit();
    twCamera();

    glEnable(GL_TEXTURE_2D);

    // the standard
    glBegin(GL_QUADS);
    glTexCoord2f(0,1);    glVertex2f(0,0);
    glTexCoord2f(0,0);    glVertex2f(0,2);
    glTexCoord2f(1,0);    glVertex2f(1,2);
    glTexCoord2f(1,1);    glVertex2f(1,0);
    glEnd();

    // cut out
    glPushMatrix();
    glTranslatef(1,0,0);
    glBegin(GL_TRIANGLES);
    glTexCoord2f(0,1);    glVertex2f(0,0);
    glTexCoord2f(0.5,0);  glVertex2f(0.5,2);
    glTexCoord2f(1,1);    glVertex2f(1,0);
    glEnd();
    glPopMatrix();

    // warped
    glPushMatrix();
    glTranslatef(2,0,0);
    glBegin(GL_QUADS);
    glTexCoord2f(0,1);    glVertex2f(0,0);
    glTexCoord2f(0,0);    glVertex2f(0.40,2);
    glTexCoord2f(1,0);    glVertex2f(0.60,2);
    glTexCoord2f(1,1);    glVertex2f(1,0);
    glEnd();
    glPopMatrix();

    // warped with interior vertices and lines
    glPushMatrix();
    glTranslatef(3,0,0);
    GLfloat vcp[] = {0,0,0, 0.5,2,0, 1,0,0, 0.5,2,0};
    GLfloat tcp[] = {0,1,   0,0,   1,1,   1,0};
    
    const int steps = 10;
    glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 2, 0, 1, 6, 2, vcp);
    glEnable(GL_MAP2_VERTEX_3);
    glMap2f(GL_MAP2_TEXTURE_COORD_2, 0, 1, 2, 2, 0, 1, 4, 2, tcp);
    glEnable(GL_MAP2_TEXTURE_COORD_2);

    glMapGrid2f(steps,0,1,steps,0,1);
    glEvalMesh2(GL_LINE,0,steps,0,steps);

    glPopMatrix();

    // warped with interior vertices and fill
    glPushMatrix();
    glTranslatef(4,0,0);
    
    glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 2, 0, 1, 6, 2, vcp);
    glEnable(GL_MAP2_VERTEX_3);
    glMap2f(GL_MAP2_TEXTURE_COORD_2, 0, 1, 2, 2, 0, 1, 4, 2, tcp);
    glEnable(GL_MAP2_TEXTURE_COORD_2);

    glMapGrid2f(steps,0,1,steps,0,1);
    glEvalMesh2(GL_FILL,0,steps,0,steps);

    glPopMatrix();

    glFlush();
    glutSwapBuffers();
}

int main(int argc, char** argv) {
    if(argc != 2) {
        printf("Usage: %s imageFile\n",argv[0]);
        exit(0);
    }
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    twInitWindowSize(1000,400);
    glutCreateWindow(argv[0]);
    glutDisplayFunc(display);
    twBoundingBox(0,5,0,2,0,0);
    twMainInit();            
    textureInit(argv[1]);
    glutMainLoop();
    return 0;
}