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PowerVR SGL Direct Quickstart Tutorial - Step 3

The SGLCONTEXT structure includes parameters determining the environment, like for example background colour, texture mapping, shadows, etc. In this example we modify a few parameters in SGLContext to introduce some thick blue fog.

#include "sgl.h"
#define RGB(r, g, b) ((sgl_uint32) (((r) << 16) | ((g) << 8) | (b)))
SGLCONTEXT SGLContext;
SGLVERTEX  Vertices[] = {
            /* x      y     z   (1/W)    col       spec.col (u/W)(v/W)*/
	    {  0.0f,240.0f,0.0f,0.1f,RGB(255,0,0),RGB(0,0,0),0.0f,0.0f},
	    {320.0f,479.0f,0.0f,0.8f,RGB(255,0,0),RGB(0,0,0),0.0f,0.0f},
	    {639.0f,240.0f,0.0f,0.1f,RGB(255,0,0),RGB(0,0,0),0.0f,0.0f},
            {320.0f,  0.0f,0.0f,0.8f,RGB(0,255,0),RGB(0,0,0),0.0f,0.0f}
		        };
int	   TriFaceData[][3] = {{0,1,2},{3,0,2}};
int        Device;

void main ()
{
   Device = sgl_create_screen_device (0,640,480,sgl_device_16bit,TRUE);
   if (Device >= 0)
   {

      SGLContext.bFogOn=TRUE;
      SGLContext.fFogR=0.5f;
      SGLContext.fFogG=0.5f;
      SGLContext.fFogB=1.0f;
      SGLContext.u32FogDensity=16;

This enables fog, and colours it blue (each R,G,B value ranges between 0 and 1, where 1 is maximum intensity. The fog density parameter ranges from 0 (no fog) to 31 (very thick fog).

      sgltri_startofframe (&SGLContext);
      sgltri_triangles    (&SGLContext, 2, TriFaceData, Vertices);
      sgltri_render       (&SGLContext);

      sgl_delete_device   (Device);
   }
}

You may view this source code.

Translating the triangle vertices will result in simple animation of the scene.
Click here to see how it's done ...

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