quakeforge/libs/video/renderer/glsl/quaketxt.vert
Bill Currie 9df7370bcd Create some shaders for quake text.
Still nothing drawn, but this gets my shader scripts into C without me
having to look at ugly strings.
2011-12-25 15:53:12 +09:00

40 lines
934 B
GLSL

/** Vertex position.
x, y, cx, cy
\a vertex provides the onscreen location at which to draw the character
(\a x, \a y) and which corner of the character cell this vertex
represents (\a cx, \a cy). \a cx and \a cy must be either 0 or 1, or
wierd things will happen with the character cell.
*/
attribute vec4 vertex;
/** The character to draw.
The quake character map supports only 256 characters, 0-255. Any other
value will give interesting results.
*/
attribute int char;
/** Coordinate in character map texture.
*/
varying vec2 st;
void
main (void)
{
int row, col;
vec2 pos, corner, uv;
const vec2 inset = (0.25, 0.25);
const vec2 size = (0.0625, 0.0625);
row = floor (char / 16);
col = mod (char, 16);
pos = vertex.xy;
corner = vertex.zw;
uv = vec2 (row, col) + inset * (1 - 2 * corner) + 8 * corner;
uv *= size;
gl_Position = mvp_mat * vec4 (pos + corner * 8, 0, 1);
st = uv + corner
}