/**
* @brief Renders the nebula using the multitexture approach.
*
* @param dt Current delta tick.
*/
static void nebu_renderMultitexture( const double dt )
{
GLfloat col[4];
int temp;
double sx, sy;
/* calculate frame to draw */
nebu_timer -= dt;
if (nebu_timer < 0.) { /* Time to change. */
temp = cur_nebu[0] - cur_nebu[1];
cur_nebu[1] = cur_nebu[0];
cur_nebu[0] += temp;
if (cur_nebu[0] >= NEBULA_Z)
cur_nebu[0] = cur_nebu[1] - 1;
else if (cur_nebu[0] < 0)
cur_nebu[0] = cur_nebu[1] + 1;
/* Change timer. */
nebu_timer += nebu_dt;
/* Case it hasn't rendered in a while so it doesn't go crazy. */
if (nebu_timer < 0)
nebu_timer = nebu_dt;
}
/* Set the colour */
col[0] = cBlue.r;
col[1] = cBlue.g;
col[2] = cBlue.b;
col[3] = (nebu_dt - nebu_timer) / nebu_dt;
/* Set up the targets */
/* Texture 0 */
nglActiveTexture( GL_TEXTURE0 );
glEnable(GL_TEXTURE_2D);
glBindTexture( GL_TEXTURE_2D, nebu_textures[cur_nebu[1]]);
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );
/* Texture 1 */
nglActiveTexture( GL_TEXTURE1 );
glEnable(GL_TEXTURE_2D);
glBindTexture( GL_TEXTURE_2D, nebu_textures[cur_nebu[0]]);
/* Prepare it */
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE );
glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_REPLACE );
glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_INTERPOLATE );
/* Colour */
glTexEnvfv( GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, col );
/* Arguments */
/* Arg0 */
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB, GL_CONSTANT );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR );
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA, GL_TEXTURE );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA );
/* Arg1 */
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_ALPHA, GL_PREVIOUS );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND1_ALPHA, GL_SRC_ALPHA );
/* Arg2 */
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE2_ALPHA, GL_CONSTANT );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND2_ALPHA, GL_SRC_ALPHA );
/* Compensate possible rumble */
spfx_getShake( &sx, &sy );
gl_matrixPush();
gl_matrixTranslate( -sx, -sy );
/* Now render! */
gl_vboActivateOffset( nebu_vboBG, GL_VERTEX_ARRAY,
sizeof(GL_FLOAT) * 0*2*4, 2, GL_FLOAT, 0 );
gl_vboActivateOffset( nebu_vboBG, GL_TEXTURE0,
sizeof(GL_FLOAT) * 1*2*4, 2, GL_FLOAT, 0 );
gl_vboActivateOffset( nebu_vboBG, GL_TEXTURE1,
sizeof(GL_FLOAT) * 2*2*4, 2, GL_FLOAT, 0 );
glDrawArrays( GL_TRIANGLE_STRIP, 0, 4 );
gl_vboDeactivate();
gl_matrixPop();
/* Set values to defaults */
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
glDisable(GL_TEXTURE_2D);
nglActiveTexture( GL_TEXTURE0 );
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
glDisable(GL_TEXTURE_2D);
/* Anything failed? */
gl_checkErr();
}
/**
* @brief Texture blitting backend for interpolated texture.
*
* Value blitted is ta*inter + tb*(1.-inter).
*
* @param ta Texture A to blit.
* @param tb Texture B to blit.
* @param inter Amount of interpolation to do.
* @param x X position of the texture on the screen.
* @param y Y position of the texture on the screen.
* @param tx X position within the texture.
* @param ty Y position within the texture.
* @param tw Texture width.
* @param th Texture height.
* @param c Colour to use (modifies texture colour).
*/
static void gl_blitTextureInterpolate( const glTexture* ta,
const glTexture* tb, const double inter,
const double x, const double y,
const double w, const double h,
const double tx, const double ty,
const double tw, const double th, const glColour *c )
{
GLfloat vertex[4*2], tex[4*2], col[4*4];
GLfloat mcol[4] = { 0., 0., 0. };
/* No interpolation. */
if (!conf.interpolate || (tb == NULL)) {
gl_blitTexture( ta, x, y, w, h, tx, ty, tw, th, c );
return;
}
/* Corner cases. */
if (inter == 1.) {
gl_blitTexture( ta, x, y, w, h, tx, ty, tw, th, c );
return;
}
else if (inter == 0.) {
gl_blitTexture( tb, x, y, w, h, tx, ty, tw, th, c );
return;
}
/* No multitexture. */
if (nglActiveTexture == NULL) {
if (inter > 0.5)
gl_blitTexture( ta, x, y, w, h, tx, ty, tw, th, c );
else
gl_blitTexture( tb, x, y, w, h, tx, ty, tw, th, c );
}
/* Set default colour. */
if (c == NULL)
c = &cWhite;
/* Bind the textures. */
/* Texture 0. */
nglActiveTexture( GL_TEXTURE0 );
glEnable(GL_TEXTURE_2D);
glBindTexture( GL_TEXTURE_2D, ta->texture);
/* Set the mode. */
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE );
/* Interpolate texture and alpha. */
glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_INTERPOLATE );
glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_INTERPOLATE );
mcol[3] = inter;
glTexEnvfv( GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, mcol );
/* Arguments. */
/* Arg0. */
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB, GL_TEXTURE0 );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR );
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA, GL_TEXTURE0 );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA );
/* Arg1. */
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB, GL_TEXTURE1 );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND1_RGB, GL_SRC_COLOR );
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_ALPHA, GL_TEXTURE1 );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND1_ALPHA, GL_SRC_ALPHA );
/* Arg2. */
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE2_RGB, GL_CONSTANT );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND2_RGB, GL_SRC_ALPHA );
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE2_ALPHA, GL_CONSTANT );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND2_ALPHA, GL_SRC_ALPHA );
/* Texture 1. */
nglActiveTexture( GL_TEXTURE1 );
glEnable(GL_TEXTURE_2D);
glBindTexture( GL_TEXTURE_2D, tb->texture);
/* Set the mode. */
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE );
/* Interpolate texture and alpha. */
glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_MODULATE );
glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_MODULATE );
/* Arguments. */
/* Arg0. */
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB, GL_PREVIOUS );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR );
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA, GL_PREVIOUS );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA );
/* Arg1. */
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB, GL_PRIMARY_COLOR );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND1_RGB, GL_SRC_COLOR );
glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_ALPHA, GL_PRIMARY_COLOR );
glTexEnvi( GL_TEXTURE_ENV, GL_OPERAND1_ALPHA, GL_SRC_ALPHA );
/* Set the colour. */
col[0] = c->r;
col[1] = c->g;
col[2] = c->b;
col[3] = c->a;
col[4] = col[0];
col[5] = col[1];
col[6] = col[2];
col[7] = col[3];
col[8] = col[0];
col[9] = col[1];
col[10] = col[2];
col[11] = col[3];
col[12] = col[0];
col[13] = col[1];
col[14] = col[2];
col[15] = col[3];
gl_vboSubData( gl_renderVBO, gl_renderVBOcolOffset, 4*4*sizeof(GLfloat), col );
gl_vboActivateOffset( gl_renderVBO, GL_COLOR_ARRAY,
gl_renderVBOcolOffset, 4, GL_FLOAT, 0 );
/* Set the vertex. */
vertex[0] = (GLfloat)x;
vertex[4] = vertex[0];
vertex[2] = vertex[0] + (GLfloat)w;
vertex[6] = vertex[2];
vertex[1] = (GLfloat)y;
vertex[3] = vertex[1];
vertex[5] = vertex[1] + (GLfloat)h;
vertex[7] = vertex[5];
gl_vboSubData( gl_renderVBO, 0, 4*2*sizeof(GLfloat), vertex );
gl_vboActivateOffset( gl_renderVBO, GL_VERTEX_ARRAY, 0, 2, GL_FLOAT, 0 );
/* Set the texture. */
tex[0] = (GLfloat)tx;
tex[4] = tex[0];
tex[2] = tex[0] + (GLfloat)tw;
tex[6] = tex[2];
tex[1] = (GLfloat)ty;
tex[3] = tex[1];
tex[5] = tex[1] + (GLfloat)th;
tex[7] = tex[5];
gl_vboSubData( gl_renderVBO, gl_renderVBOtexOffset, 4*2*sizeof(GLfloat), tex );
gl_vboActivateOffset( gl_renderVBO, GL_TEXTURE0,
gl_renderVBOtexOffset, 2, GL_FLOAT, 0 );
gl_vboActivateOffset( gl_renderVBO, GL_TEXTURE1,
gl_renderVBOtexOffset, 2, GL_FLOAT, 0 );
/* Draw. */
glDrawArrays( GL_TRIANGLE_STRIP, 0, 4 );
/* Clear state. */
gl_vboDeactivate();
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
glDisable(GL_TEXTURE_2D);
nglActiveTexture( GL_TEXTURE0 );
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
glDisable(GL_TEXTURE_2D);
/* anything failed? */
gl_checkErr();
}
