Pro OpenGL ES for iOS

186 CHAPTER 6: Will It Blend?^

First, we revisit our old friend, drawInRect(). We’re back to only a single texture, going

up and down. The color support has also been stripped out. So, you should have

something like Listing 6-4. And make sure that you are still loading a second texture.

Listing 6-4. drawInRect() Revisited, Modified for Multitexture Support

• (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
  {
  static const GLfloat squareVertices[] =
  {
  -0.5, -0.5, 0.0,
  0.5, -0.5, 0.0,
  -0.5, 0.5, 0.0,
  0.5, 0.5, 0.0
  };

static GLfloat textureCoords[] =

{

0.0, 0.0,

1.0, 0.0,

0.0, 1.0,

1.0, 1.0

};

static float transY = 0.0;

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

[self setClipping];

glClearColor(0.0, 0.0,0.0, 1.0);

glClear(GL_COLOR_BUFFER_BIT);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

//Set up for using textures.

glEnable(GL_TEXTURE_2D);

glEnableClientState(GL_VERTEX_ARRAY);

glVertexPointer(3, GL_FLOAT, 0, squareVertices);

glEnableClientState(GL_TEXTURE_COORD_ARRAY);

glClientActiveTexture(GL_TEXTURE0); //1

glTexCoordPointer(2, GL_FLOAT,0,textureCoords);

glClientActiveTexture(GL_TEXTURE1); //2

glTexCoordPointer(2, GL_FLOAT,0,textureCoords);

glLoadIdentity();

glTranslatef(0.0, (GLfloat)(sinf(transY)/2.0), -2.5);