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author | rodri <rgl@antares-labs.eu> | 2024-05-20 20:20:48 +0000 |
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committer | rodri <rgl@antares-labs.eu> | 2024-05-20 20:20:48 +0000 |
commit | d3516b11559657935d70829c672f29393e857b8e (patch) | |
tree | 13c2b87f9daf6bd813f43c750fef52d5b8b34ddd /render.c | |
parent | 6e461add61d35d23f733cffb5064a286419b79b0 (diff) | |
download | libgraphics-d3516b11559657935d70829c672f29393e857b8e.tar.gz libgraphics-d3516b11559657935d70829c672f29393e857b8e.tar.bz2 libgraphics-d3516b11559657935d70829c672f29393e857b8e.zip |
fix the perspective projection and add inverse xform functions.
Diffstat (limited to 'render.c')
-rw-r--r-- | render.c | 112 |
1 files changed, 0 insertions, 112 deletions
@@ -52,118 +52,6 @@ isfacingback(Primitive p) return sa <= 0; } -/* - * transforms p from e's reference frame into - * the world. - */ -Point3 -model2world(Entity *e, Point3 p) -{ - return invrframexform3(p, *e); -} - -/* - * transforms p from the world reference frame - * to c's one (aka Viewing Coordinate System). - */ -Point3 -world2vcs(Camera *c, Point3 p) -{ - return rframexform3(p, *c); -} - -/* - * projects p from the VCS to clip space, placing - * p.[xyz] ∈ (-∞,-w)∪[-w,w]∪(w,∞) where [-w,w] - * represents the visibility volume. - * - * the clipping planes are: - * - * | -w | w | - * +----------------+ - * | left | right | - * | bottom | top | - * | far | near | - */ -Point3 -vcs2clip(Camera *c, Point3 p) -{ - return xform3(p, c->proj); -} - -Point3 -world2clip(Camera *c, Point3 p) -{ - return vcs2clip(c, world2vcs(c, p)); -} - -/* - * performs the perspective division, placing - * p.[xyz] ∈ [-1,1] and p.w = 1/z - * (aka Normalized Device Coordinates). - * - * p.w is kept as z⁻¹ so we can later do - * perspective-correct attribute interpolation. - */ -static Point3 -clip2ndc(Point3 p) -{ - p.w = p.w == 0? 1: 1.0/p.w; - p.x *= p.w; - p.y *= p.w; - p.z *= p.w; - return p; -} - -/* - * scales p to fit the destination viewport, - * placing p.x ∈ [0,width], p.y ∈ [0,height], - * p.z ∈ [0,1] and leaving p.w intact. - */ -static Point3 -ndc2viewport(Framebuf *fb, Point3 p) -{ - Matrix3 view = { - Dx(fb->r)/2.0, 0, 0, Dx(fb->r)/2.0, - 0, -Dy(fb->r)/2.0, 0, Dy(fb->r)/2.0, - 0, 0, 1.0/2.0, 1.0/2.0, - 0, 0, 0, 1, - }; - double w; - - w = p.w; - p.w = 1; - p = xform3(p, view); - p.w = w; - return p; -} - -void -perspective(Matrix3 m, double fov, double a, double n, double f) -{ - double cotan; - - cotan = 1/tan(fov/2); - identity3(m); - m[0][0] = cotan/a; - m[1][1] = cotan; - m[2][2] = (f+n)/(f-n); - m[2][3] = -2*f*n/(f-n); - m[3][2] = -1; -} - -void -orthographic(Matrix3 m, double l, double r, double b, double t, double n, double f) -{ - identity3(m); - m[0][0] = 2/(r - l); - m[1][1] = 2/(t - b); - m[2][2] = -2/(f - n); - m[0][3] = -(r + l)/(r - l); - m[1][3] = -(t + b)/(t - b); - m[2][3] = -(f + n)/(f - n); -} - static void rasterize(Rastertask *task) { |