static void
Init(void)
{
static const GLubyte teximage[2][2][4] = {
{ { 255, 255, 255, 255}, { 128, 128, 128, 255} },
{ { 128, 128, 128, 255}, { 255, 255, 255, 255} }
};
printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
if (!GLEW_EXT_fog_coord) {
printf("GL_EXT_fog_coord not supported!\n");
}
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0,
GL_RGBA, GL_UNSIGNED_BYTE, teximage);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glClearColor(0.1f, 0.1f, 0.1f, 0.0f);
glDepthFunc(GL_LEQUAL);
glEnable(GL_DEPTH_TEST);
glShadeModel(GL_SMOOTH);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
glFogfv(GL_FOG_COLOR, fogColor);
glHint(GL_FOG_HINT, GL_NICEST);
fogCoord = SetFogCoord(GL_TRUE); /* try to enable fog_coord */
fogMode = SetFogMode(1);
glEnableClientState(GL_VERTEX_ARRAY);
glVertexPointer(3, GL_FLOAT, 0, vertex_pointer);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glTexCoordPointer(2, GL_FLOAT, 0, texcoord_pointer);
if (GLEW_EXT_fog_coord) {
glEnableClientState(GL_FOG_COORDINATE_ARRAY_EXT);
glFogCoordPointerEXT(GL_FLOAT, 0, fogcoord_pointer);
}
Reset();
}
static void
Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 'a':
Arrays = !Arrays;
break;
case 'f':
case 'm':
fogMode = SetFogMode(fogMode + 1);
break;
case 'D':
fogDensity += 0.05;
SetFogMode(fogMode);
break;
case 'd':
if (fogDensity > 0.0) {
fogDensity -= 0.05;
}
SetFogMode(fogMode);
break;
case 's':
if (fogStart > 0.0) {
fogStart -= 0.25;
}
SetFogMode(fogMode);
break;
case 'S':
if (fogStart < 100.0) {
fogStart += 0.25;
}
SetFogMode(fogMode);
break;
case 'e':
if (fogEnd > 0.0) {
fogEnd -= 0.25;
}
SetFogMode(fogMode);
break;
case 'E':
if (fogEnd < 100.0) {
fogEnd += 0.25;
}
SetFogMode(fogMode);
break;
case 'c':
fogCoord = SetFogCoord(fogCoord ^ GL_TRUE);
break;
case 't':
Texture = !Texture;
break;
case 'z':
camz -= 0.1;
break;
case 'Z':
camz += 0.1;
break;
case 'r':
Reset();
break;
case 27:
exit(0);
break;
}
glutPostRedisplay();
}
void RenderHeightMap(BYTE pHeightMap[])
{
int X = 0, Y = 0; // Create some variables to walk the array with.
int x, y, z; // Create some variables for readability
bool bSwitchSides = false;
// Make sure our height data is valid
if(!pHeightMap) return;
// Activate the first texture ID and bind the tree background to it
glActiveTextureARB(GL_TEXTURE0_ARB);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, g_Texture[0]);
// If we want detail texturing on, let's render the second texture
if(g_bDetail)
{
// Activate the second texture ID and bind the fog texture to it
glActiveTextureARB(GL_TEXTURE1_ARB);
glEnable(GL_TEXTURE_2D);
// Here we turn on the COMBINE properties and increase our RGB
// gamma for the detail texture. 2 seems to work just right.
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
glTexEnvi(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2);
// Bind the detail texture
glBindTexture(GL_TEXTURE_2D, g_Texture[1]);
// Now we want to enter the texture matrix. This will allow us
// to change the tiling of the detail texture.
glMatrixMode(GL_TEXTURE);
// Reset the current matrix and apply our chosen scale value
glLoadIdentity();
glScalef((float)g_DetailScale, (float)g_DetailScale, 1);
// Leave the texture matrix and set us back in the model view matrix
glMatrixMode(GL_MODELVIEW);
}
// We want to render triangle strips
glBegin( GL_TRIANGLE_STRIP );
// Go through all of the rows of the height map
for ( X = 0; X <= MAP_SIZE; X += STEP_SIZE )
{
// Check if we need to render the opposite way for this column
if(bSwitchSides)
{
// Render a column of the terrain, for this current X.
// We start at MAP_SIZE and render down to 0.
for ( Y = MAP_SIZE; Y >= 0; Y -= STEP_SIZE )
{
// Get the (X, Y, Z) value for the bottom left vertex
x = X;
y = Height(pHeightMap, X, Y );
z = Y;
/////// * /////////// * /////////// * NEW * /////// * /////////// * /////////// *
// Set the fog coordinate for this vertex, depending on it's height
// and the current depth of the fog.
SetFogCoord(g_FogDepth, (float)y);
/////// * /////////// * /////////// * NEW * /////// * /////////// * /////////// *
// Set the current texture coordinate and render the vertex
SetTextureCoord( (float)x, (float)z );
glVertex3i(x, y, z);
// Get the (X, Y, Z) value for the bottom right vertex
x = X + STEP_SIZE;
y = Height(pHeightMap, X + STEP_SIZE, Y );
z = Y;
/////// * /////////// * /////////// * NEW * /////// * /////////// * /////////// *
// Set the fog coordinate for this vertex
SetFogCoord(g_FogDepth, (float)y);
/////// * /////////// * /////////// * NEW * /////// * /////////// * /////////// *
// Set the current texture coordinate and render the vertex
SetTextureCoord( (float)x, (float)z );
glVertex3i(x, y, z);
}
}
else
{
// Render a column of the terrain, for this current X.
// We start at 0 and render down up to MAP_SIZE.
for ( Y = 0; Y <= MAP_SIZE; Y += STEP_SIZE )
{
// Get the (X, Y, Z) value for the bottom right vertex
x = X + STEP_SIZE;
y = Height(pHeightMap, X + STEP_SIZE, Y );
z = Y;
/////// * /////////// * /////////// * NEW * /////// * /////////// * /////////// *
// Set the fog coordinate for this vertex
SetFogCoord(g_FogDepth, (float)y);
/////// * /////////// * /////////// * NEW * /////// * /////////// * /////////// *
// Set the current texture coordinate and render the vertex
SetTextureCoord( (float)x, (float)z );
glVertex3i(x, y, z);
// Get the (X, Y, Z) value for the bottom left vertex
x = X;
y = Height(pHeightMap, X, Y );
z = Y;
/////// * /////////// * /////////// * NEW * /////// * /////////// * /////////// *
// Set the fog coordinate for this vertex
SetFogCoord(g_FogDepth, (float)y);
/////// * /////////// * /////////// * NEW * /////// * /////////// * /////////// *
// Set the current texture coordinate and render the vertex
SetTextureCoord( (float)x, (float)z );
glVertex3i(x, y, z);
}
}
// Switch the direction the column renders to allow the fluid tri strips
bSwitchSides = !bSwitchSides;
}
// Stop rendering triangle strips
glEnd();
// Turn the second multitexture pass off
glActiveTextureARB(GL_TEXTURE1_ARB);
glDisable(GL_TEXTURE_2D);
// Turn the first multitexture pass off
glActiveTextureARB(GL_TEXTURE0_ARB);
glDisable(GL_TEXTURE_2D);
}
