From f98dcc45225fa78341aba06137b05b9b6b89cb12 Mon Sep 17 00:00:00 2001
From: rodri <rgl@antares-labs.eu>
Date: Thu, 29 Aug 2024 18:19:15 +0000
Subject: implement a general raster interface for the framebuffers.

got a bit tired of having to add a ulong *buf every time
i needed to get some data out of the shaders, so i made
it possible to create as many extra buffers as needed,
which then can be addressed from the fragment shader
and drawn using the same drawing routines that were used
for the color buffer.

these so called Rasters are very similar to the OpenGL
FBOs, in case you are familiar, but we address them by
strings instead of numbers. and they can also be used as
textures if you create one (see alloctexture) and then
memdraw into it after every shot.
---
 render.c | 63 ++++++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 44 insertions(+), 19 deletions(-)

(limited to 'render.c')

diff --git a/render.c b/render.c
index 71edf99..7b1bbb8 100644
--- a/render.c
+++ b/render.c
@@ -35,7 +35,7 @@ ul2col(ulong l)
 }
 
 static void
-pixel(Framebuf *fb, Point p, Color c, int blend)
+pixel(Raster *fb, Point p, Color c, int blend)
 {
 	Color dc;
 
@@ -50,13 +50,31 @@ pixel(Framebuf *fb, Point p, Color c, int blend)
 }
 
 static void
-pixeln(Framebuf *fb, Point p, Color c)
+fsparams_toraster(FSparams *sp, char *rname, void *v)
 {
-	ulong *dst;
-
-	dst = fb->nb;
-	c.a = 1;
-	dst[Dx(fb->r)*p.y + p.x] = col2ul(c);
+	Framebuf *fb;
+	Raster *r;
+	ulong c, z;
+
+	/* keep the user away from the color buffer */
+	if(rname == nil || v == nil)
+		return;
+
+	fb = sp->su->fb;
+	r = fb->fetchraster(fb, rname);
+	if(r == nil)
+		return;
+
+	switch(r->chan){
+	case COLOR32:
+		c = col2ul(*(Color*)v);
+		rasterput(r, sp->p, &c);
+		break;
+	case FLOAT32:
+		z = *(float*)v;
+		rasterput(r, sp->p, &z);
+		break;
+	}
 }
 
 static int
@@ -117,16 +135,19 @@ squashAbuf(Framebuf *fb, int blend)
 {
 	Abuf *buf;
 	Astk *stk;
+	Raster *cr, *zr;
 	int i, j;
 
 	buf = &fb->abuf;
+	cr = fb->rasters;
+	zr = cr->next;
 	for(i = 0; i < buf->nact; i++){
 		stk = buf->act[i];
 		j = stk->size;
 		while(j--)
-			pixel(fb, stk->p, stk->items[j].c, blend);
+			pixel(cr, stk->p, stk->items[j].c, blend);
 		/* write to the depth buffer as well */
-		fb->zb[stk->p.x + stk->p.y*Dx(fb->r)] = stk->items[0].z;
+		putdepth(zr, stk->p, stk->items[0].z);
 	}
 }
 
@@ -149,6 +170,7 @@ static void
 rasterize(Rastertask *task)
 {
 	SUparams *params;
+	Raster *cr, *zr;
 	Primitive prim;
 	FSparams fsp;
 	Triangle2 t;
@@ -164,6 +186,10 @@ rasterize(Rastertask *task)
 	prim = task->p;
 	fsp.su = params;
 	memset(&fsp.v, 0, sizeof fsp.v);
+	fsp.toraster = fsparams_toraster;
+
+	cr = params->fb->rasters;
+	zr = cr->next;
 
 	switch(prim.type){
 	case PPoint:
@@ -171,9 +197,9 @@ rasterize(Rastertask *task)
 
 		z = fclamp(prim.v[0].p.z, 0, 1);
 		if(params->camera->enabledepth){
-			if(z <= params->fb->zb[p.x + p.y*Dx(params->fb->r)])
+			if(z <= getdepth(zr, p))
 				break;
-			params->fb->zb[p.x + p.y*Dx(params->fb->r)] = z;
+			putdepth(zr, p, z);
 		}
 
 		fsp.v = dupvertex(&prim.v[0]);
@@ -182,7 +208,7 @@ rasterize(Rastertask *task)
 		if(params->camera->enableAbuff)
 			pushtoAbuf(params->fb, p, c, z);
 		else
-			pixel(params->fb, p, c, params->camera->enableblend);
+			pixel(cr, p, c, params->camera->enableblend);
 		delvattrs(&fsp.v);
 		break;
 	case PLine:
@@ -220,9 +246,9 @@ rasterize(Rastertask *task)
 			z = flerp(prim.v[0].p.z, prim.v[1].p.z, perc);
 			/* TODO get rid of the bounds check and make sure the clipping doesn't overflow */
 			if(params->camera->enabledepth){
-				if(!ptinrect(p, params->fb->r) || z <= params->fb->zb[p.x + p.y*Dx(params->fb->r)])
+				if(!ptinrect(p, params->fb->r) || z <= getdepth(zr, p))
 					goto discard;
-				params->fb->zb[p.x + p.y*Dx(params->fb->r)] = z;
+				putdepth(zr, p, z);
 			}
 
 			/* interpolate z⁻¹ and get actual z */
@@ -238,7 +264,7 @@ rasterize(Rastertask *task)
 			if(params->camera->enableAbuff)
 				pushtoAbuf(params->fb, p, c, z);
 			else
-				pixel(params->fb, p, c, params->camera->enableblend);
+				pixel(cr, p, c, params->camera->enableblend);
 			delvattrs(&fsp.v);
 discard:
 			if(steep) SWAP(int, &p.x, &p.y);
@@ -272,9 +298,9 @@ discard:
 
 				z = fberp(prim.v[0].p.z, prim.v[1].p.z, prim.v[2].p.z, bc);
 				if(params->camera->enabledepth){
-					if(z <= params->fb->zb[p.x + p.y*Dx(params->fb->r)])
+					if(z <= getdepth(zr, p))
 						continue;
-					params->fb->zb[p.x + p.y*Dx(params->fb->r)] = z;
+					putdepth(zr, p, z);
 				}
 
 				/* interpolate z⁻¹ and get actual z */
@@ -292,8 +318,7 @@ discard:
 				if(params->camera->enableAbuff)
 					pushtoAbuf(params->fb, p, c, z);
 				else
-					pixel(params->fb, p, c, params->camera->enableblend);
-				pixeln(params->fb, p, fsp.v.n);
+					pixel(cr, p, c, params->camera->enableblend);
 				delvattrs(&fsp.v);
 			}
 		break;
-- 
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