display.c

linux环境下jpeg编解码算法的实现

#include <math.h>
#include <zevio/gpu_factory.h>
#include <GLES/egl.h>

#include "display.h"

#define OGLFIXED_SHIFT				16
#define OGLFIXED_ONE				( 1 << OGLFIXED_SHIFT )
#define OGLFLOAT_TO_FIXED(_x)		( (_x) * (OGLFIXED_ONE) )
#define NEARCLIP		            1.0f
#define FARCLIP			            500.0f
#define FOV				            90
#define PI				            3.14159f

GLfloat vertex[] = {
	-1.0f, -1.0f,  0.0f,
	1.0f, -1.0f,  0.0f,
	-1.0f,  1.0f,  0.0f,
	1.0f,  1.0f,  0.0f,
};

GLfloat texCoord[] = {
	0.0, 1.0,
	1.0, 1.0,
	0.0, 0.0,
	1.0, 0.0,
};

const int bitmapDimensions[2]={800,600};

static void reshape(int width, int height)
{
	glMatrixMode( GL_PROJECTION );
	glLoadIdentity();

	glViewport(0, 0, width, height);
	{
		float aspect, top, bottom, left, right;

		aspect = (float)width/(float)height;
		top = tan( (float)FOV * PI / 360.f ) * NEARCLIP;
		bottom = -top;
		left = aspect*top;
		right = -left;
		glFrustumx( OGLFLOAT_TO_FIXED( left ), OGLFLOAT_TO_FIXED( right  ),
		            OGLFLOAT_TO_FIXED( top ),  OGLFLOAT_TO_FIXED( bottom ),
		            OGLFLOAT_TO_FIXED( NEARCLIP ), OGLFLOAT_TO_FIXED( FARCLIP ) );
	}

	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

void display_init()
{
	reshape(SVGA_WINDOW_WIDTH,SVGA_WINDOW_HEIGHT); // init view

	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LEQUAL);

	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
	glClearDepthf(1.0f);

	glShadeModel(GL_FLAT);

	int texWidth, texHeight;
	for (texWidth = 16; texWidth < bitmapDimensions[0]; texWidth <<= 1);
	for (texHeight = 16; texHeight < bitmapDimensions[1]; texHeight <<= 1);

	int i;
	for (i = 0; i < 4; i++)
	{
		vertex[i*3]     *= ((GLfloat)bitmapDimensions[0]/bitmapDimensions[1]);
		texCoord[i*2]   *= ((GLfloat)bitmapDimensions[0])/texWidth;
		texCoord[i*2+1] *= ((GLfloat)bitmapDimensions[1])/texHeight;
	}
}

static void redraw()
{
	glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	glEnableClientState(GL_VERTEX_ARRAY | GL_TEXTURE_COORD_ARRAY);
	glVertexPointer(3, GL_FLOAT, 0, vertex);
	glTexCoordPointer(2, GL_FLOAT, 0, texCoord);

	glLoadIdentity();
	glTranslatef(0.0f,0.0f,-1.0f);

	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

	glFlush ();
	zevio2d_wait_for_vsync();
	GPU_Factory_SwapFrameBuffers();
}

void loadBitmapTexture(void *pixels, int width, int height, unsigned short *base, unsigned long offset)
{
	int rowOffset = CALC_OFFSET_TO_Y(offset);
	int colOffset = CALC_OFFSET_TO_X(offset);

	unsigned short *addr;
	int i,j;
	int x,y=rowOffset;
	for (i=0;i<height;i++,y++)
	{
		x=colOffset;
		for (j=0;j<width;j++,x++)
		{
			addr = base + (((y)/8)*32 + ((x)/32)) * 256 + (((y)%8)*32 + ((x)%32));
			*addr = *(((unsigned short*)pixels)+i*width+j);
		}
	}
}

void display_pixels(void *pData, unsigned short *gpuMem, unsigned long offset)
{
//	loadBitmapTexture(pData,bitmapDimensions[0],bitmapDimensions[1],gpuMem,offset);
	glZevioTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, bitmapDimensions[0], bitmapDimensions[1], 0,
	                  GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1, pData, offset);
	glEnable(GL_TEXTURE_2D);
	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);

	redraw();
}