/**
* @brief Draws a circle in a rectangle.
*
* @param cx X position of the center in screen coordinates..
* @param cy Y position of the center in screen coordinates.
* @param r Radius of the circle.
* @param rx X position of the rectangle limiting the circle in screen coords.
* @param ry Y position of the rectangle limiting the circle in screen coords.
* @param rw Width of the limiting rectangle.
* @param rh Height of the limiting rectangle.
* @param c Colour to use.
*/
void gl_drawCircleInRect( const double cx, const double cy, const double r,
const double rx, const double ry, const double rw, const double rh,
const glColour *c, int filled )
{
int i, j;
double rxw,ryh, x,y,p, w,h, tx,ty, tw,th, r2;
GLfloat vertex[2*OPENGL_RENDER_VBO_SIZE], col[4*OPENGL_RENDER_VBO_SIZE];
rxw = rx+rw;
ryh = ry+rh;
/* is offscreen? */
if ((cx+r < rx) || (cy+r < ry) || (cx-r > rxw) || (cy-r > ryh))
return;
/* can be drawn normally? */
else if ((cx-r > rx) && (cy-r > ry) && (cx+r < rxw) && (cy+r < ryh)) {
gl_drawCircle( cx, cy, r, c, filled );
return;
}
/* Case if filled. */
if (filled) {
r2 = 2.*r;
/* Clamp bottom left. */
x = CLAMP( rx, rxw, cx-r );
y = CLAMP( ry, ryh, cy-r );
/* Clamp width. */
w = CLAMP( rx, rxw, cx+r ) - x;
h = CLAMP( ry, ryh, cy+r ) - y;
/* Calculate texture bottom left. */
tx = x - (cx-r);
tx *= gl_circle->srw / r2; /* Transform to unitary coordinates. */
ty = y - (cy-r);
ty *= gl_circle->srh / r2;
/* Calculate dimensions of texture. */
tw = w/r2 * gl_circle->srw;
th = h/r2 * gl_circle->srh;
/* Render. */
gl_blitTexture( gl_circle, x, y, w, h, tx, ty, tw, th, c );
return;
}
/* Starting parameters. */
i = 0;
x = 0;
y = r;
p = (5. - (r*4.)) / 4.;
PIXEL( cx, cy+y );
PIXEL( cx, cy-y );
PIXEL( cx+y, cy );
PIXEL( cx-y, cy );
while (x<y) {
x++;
if (p < 0) p += 2*(double)(x)+1;
else p += 2*(double)(x-(--y))+1;
if (x==0) {
PIXEL( cx, cy+y );
PIXEL( cx, cy-y );
PIXEL( cx+y, cy );
PIXEL( cx-y, cy );
}
else
if (x==y) {
PIXEL( cx+x, cy+y );
PIXEL( cx-x, cy+y );
PIXEL( cx+x, cy-y );
PIXEL( cx-x, cy-y );
}
else
if (x<y) {
PIXEL( cx+x, cy+y );
PIXEL( cx-x, cy+y );
PIXEL( cx+x, cy-y );
PIXEL( cx-x, cy-y );
PIXEL( cx+y, cy+x );
PIXEL( cx-y, cy+x );
PIXEL( cx+y, cy-x );
PIXEL( cx-y, cy-x );
}
}
gl_vboSubData( gl_renderVBO, 0, i*2*sizeof(GLfloat), vertex );
gl_vboActivateOffset( gl_renderVBO, GL_VERTEX_ARRAY, 0, 2, GL_FLOAT, 0 );
/* Set up the colour. */
for (j=0; j<i; j++) {
col[4*j+0] = c->r;
col[4*j+1] = c->g;
col[4*j+2] = c->b;
col[4*j+3] = c->a;
}
gl_vboSubData( gl_renderVBO, gl_renderVBOcolOffset, i*4*sizeof(GLfloat), col );
gl_vboActivateOffset( gl_renderVBO, GL_COLOR_ARRAY,
gl_renderVBOcolOffset, 4, GL_FLOAT, 0 );
/* Draw. */
glDrawArrays( GL_POINTS, 0, i );
/* Clear state. */
gl_vboDeactivate();
}
/**
* @brief Draws a circle in a rectangle.
*
* @param cx X position of the center in screen coordinates..
* @param cy Y position of the center in screen coordinates.
* @param r Radius of the circle.
* @param rx X position of the rectangle limiting the circle in screen coords.
* @param ry Y position of the rectangle limiting the circle in screen coords.
* @param rw Width of the limiting rectangle.
* @param rh Height of the limiting rectangle.
* @param c Colour to use.
*/
void gl_drawCircleInRect( const double cx, const double cy, const double r,
const double rx, const double ry, const double rw, const double rh,
const glColour *c, int filled )
{
int i, j;
double rxw,ryh, x,y,p, w,h;
GLfloat vertex[2*OPENGL_RENDER_VBO_SIZE], col[4*OPENGL_RENDER_VBO_SIZE];
rxw = rx+rw;
ryh = ry+rh;
/* is offscreen? */
if ((cx+r < rx) || (cy+r < ry) || (cx-r > rxw) || (cy-r > ryh))
return;
/* can be drawn normally? */
else if ((cx-r > rx) && (cy-r > ry) && (cx+r < rxw) && (cy+r < ryh)) {
gl_drawCircle( cx, cy, r, c, filled );
return;
}
/* Case if filled. */
if (filled) {
x = CLAMP( rx, rxw, cx-r );
y = CLAMP( ry, ryh, cy-r );
w = CLAMP( 0., rxw-x, 2.*r );
h = CLAMP( 0., ryh-y, 2.*r );
gl_blitTexture( gl_circle, x, y, w, h,
(x-(cx-r))/(2.*r) * gl_circle->srw,
(y-(cy-r))/(2.*r) * gl_circle->srh,
(w/(2.*r)) * gl_circle->srw,
(h/(2.*r)) * gl_circle->srh, c );
return;
}
/* Starting parameters. */
i = 0;
x = 0;
y = r;
p = (5. - (r*4.)) / 4.;
PIXEL( cx, cy+y );
PIXEL( cx, cy-y );
PIXEL( cx+y, cy );
PIXEL( cx-y, cy );
while (x<y) {
x++;
if (p < 0) p += 2*(double)(x)+1;
else p += 2*(double)(x-(--y))+1;
if (x==0) {
PIXEL( cx, cy+y );
PIXEL( cx, cy-y );
PIXEL( cx+y, cy );
PIXEL( cx-y, cy );
}
else
if (x==y) {
PIXEL( cx+x, cy+y );
PIXEL( cx-x, cy+y );
PIXEL( cx+x, cy-y );
PIXEL( cx-x, cy-y );
}
else
if (x<y) {
PIXEL( cx+x, cy+y );
PIXEL( cx-x, cy+y );
PIXEL( cx+x, cy-y );
PIXEL( cx-x, cy-y );
PIXEL( cx+y, cy+x );
PIXEL( cx-y, cy+x );
PIXEL( cx+y, cy-x );
PIXEL( cx-y, cy-x );
}
}
gl_vboSubData( gl_renderVBO, 0, i*2*sizeof(GLfloat), vertex );
gl_vboActivateOffset( gl_renderVBO, GL_VERTEX_ARRAY, 0, 2, GL_FLOAT, 0 );
/* Set up the colour. */
for (j=0; j<i; j++) {
col[4*j+0] = c->r;
col[4*j+1] = c->g;
col[4*j+2] = c->b;
col[4*j+3] = c->a;
}
gl_vboSubData( gl_renderVBO, gl_renderVBOcolOffset, i*4*sizeof(GLfloat), col );
gl_vboActivateOffset( gl_renderVBO, GL_COLOR_ARRAY,
gl_renderVBOcolOffset, 4, GL_FLOAT, 0 );
/* Draw. */
glDrawArrays( GL_POINTS, 0, i );
/* Clear state. */
gl_vboDeactivate();
}
