From 7705fa326336feba1a66d5a6ca8a7c27771e4c5f Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@member.fsf.org>
Date: Fri, 10 Jul 2020 15:20:23 +0300
Subject: [PATCH] zbuffer done

---
 src/3dgfx/polyfill.h |    2 +-
 src/3dgfx/polytmpl.h |   21 ++++++++++++---------
 src/glut/main.c      |   20 +++++++++++++++++---
 src/scr/polytest.c   |   32 +++++++++++++++++++++++++-------
 4 files changed, 55 insertions(+), 20 deletions(-)

diff --git a/src/3dgfx/polyfill.h b/src/3dgfx/polyfill.h
index fed8eda..6c95667 100644
--- a/src/3dgfx/polyfill.h
+++ b/src/3dgfx/polyfill.h
@@ -66,7 +66,7 @@ struct pvertex {
 	int32_t x, y; /* 24.8 fixed point */
 	int32_t u, v; /* 16.16 fixed point */
 	int32_t r, g, b, a;  /* int 0-255 */
-	uint16_t z;	/* 0-65535 */
+	int32_t z;	/* 0-65535 */
 };
 
 struct pimage {
diff --git a/src/3dgfx/polytmpl.h b/src/3dgfx/polytmpl.h
index 01bbd01..167d5e1 100644
--- a/src/3dgfx/polytmpl.h
+++ b/src/3dgfx/polytmpl.h
@@ -13,7 +13,7 @@ static uint32_t SCANEDGE(struct pvertex *v0, struct pvertex *v1, struct pvertex
 	int32_t u, v, du, dv, uslope, vslope;
 #endif
 #ifdef ZBUF
-	int z, dz, zslope;
+	int32_t z, dz, zslope;
 #endif
 	int32_t start_idx, end_idx;
 
@@ -115,7 +115,7 @@ void POLYFILL(struct pvertex *pv, int nverts)
 	int32_t u, v, du, dv, uslope, vslope;
 #endif
 #ifdef ZBUF
-	int z, dz, zslope;
+	int32_t z, dz, zslope;
 #endif
 
 	for(i=1; i<nverts; i++) {
@@ -300,6 +300,9 @@ void POLYFILL(struct pvertex *pv, int nverts)
 
 		/* go across the scanline interpolating if necessary */
 		while(x <= right[i].x) {
+			/*if(x == (180 << 8) && i == 174) {
+				asm("int $3");
+			}*/
 #if defined(GOURAUD) || defined(TEXMAP) || defined(BLEND_ALPHA) || defined(BLEND_ADD)
 			int cr, cg, cb;
 #endif
@@ -311,11 +314,11 @@ void POLYFILL(struct pvertex *pv, int nverts)
 #endif
 
 #ifdef ZBUF
-			int cz = z;
+			int32_t cz = z;
 			z += zslope;
 
 			if(z <= *zptr) {
-				*zptr = z;
+				*zptr++ = z;
 			} else {
 #ifdef GOURAUD
 				r += rslope;
@@ -329,9 +332,12 @@ void POLYFILL(struct pvertex *pv, int nverts)
 				u += uslope;
 				v += vslope;
 #endif
-				goto skip_pixel;
+				/* skip pixel */
+				pixptr++;
+				zptr++;
+				x += 256;
+				continue;
 			}
-			zptr++;
 #endif
 
 #ifdef GOURAUD
@@ -407,9 +413,6 @@ void POLYFILL(struct pvertex *pv, int nverts)
 			color = G3D_PACK_RGB(cr, cg, cb);
 #endif
 
-#ifdef ZBUF
-skip_pixel:
-#endif
 #ifdef DEBUG_OVERDRAW
 			*pixptr++ += DEBUG_OVERDRAW;
 #else
diff --git a/src/glut/main.c b/src/glut/main.c
index fb663e6..79833d9 100644
--- a/src/glut/main.c
+++ b/src/glut/main.c
@@ -73,7 +73,7 @@ static cgm_quat rot = {0, 0, 0, 1};
 int main(int argc, char **argv)
 {
 	glutInit(&argc, argv);
-	glutInitWindowSize(800, 600);
+	glutInitWindowSize(1280, 960);
 	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
 	glutCreateWindow("Mindlapse");
 
@@ -428,14 +428,28 @@ static void map_mouse_pos(int *xp, int *yp)
 
 static void mouse_button(int bn, int st, int x, int y)
 {
+	int bit;
+
 	map_mouse_pos(&x, &y);
 	mouse_x = x;
 	mouse_y = y;
 
+	switch(bn) {
+	case GLUT_LEFT_BUTTON:
+		bit = 0;
+		break;
+	case GLUT_RIGHT_BUTTON:
+		bit = 1;
+		break;
+	case GLUT_MIDDLE_BUTTON:
+		bit = 2;
+		break;
+	}
+
 	if(st == GLUT_DOWN) {
-		mouse_bmask |= 1 << bn;
+		mouse_bmask |= 1 << bit;
 	} else {
-		mouse_bmask &= ~(1 << bn);
+		mouse_bmask &= ~(1 << bit);
 	}
 }
 
diff --git a/src/scr/polytest.c b/src/scr/polytest.c
index ca04256..6648547 100644
--- a/src/scr/polytest.c
+++ b/src/scr/polytest.c
@@ -42,6 +42,9 @@ static int use_bsp = 0;
 static uint16_t *lowres_pixels;
 static int lowres_width, lowres_height;
 
+static int use_zbuf;
+
+
 struct screen *polytest_screen(void)
 {
 	return &scr;
@@ -94,7 +97,7 @@ static void start(long trans_time)
 {
 	g3d_matrix_mode(G3D_PROJECTION);
 	g3d_load_identity();
-	g3d_perspective(50.0, 1.3333333, 0.5, 100.0);
+	g3d_perspective(50.0, 1.3333333, 1.0, 10.0);
 
 	g3d_enable(G3D_CULL_FACE);
 	g3d_enable(G3D_LIGHTING);
@@ -103,7 +106,7 @@ static void start(long trans_time)
 	g3d_polygon_mode(G3D_GOURAUD);
 	g3d_enable(G3D_TEXTURE_2D);
 
-	g3d_enable(G3D_DEPTH_TEST);
+	g3d_clear_color(20, 30, 50);
 }
 
 static void update(void)
@@ -119,9 +122,14 @@ static void draw(void)
 
 	update();
 
-	//memset16(fb_pixels, PACK_RGB16(20, 30, 50), FB_WIDTH * FB_HEIGHT);
-	g3d_clear_color(20, 30, 50);
-	g3d_clear(G3D_COLOR_BUFFER_BIT | G3D_DEPTH_BUFFER_BIT);
+	if(use_zbuf) {
+		g3d_clear(G3D_COLOR_BUFFER_BIT | G3D_DEPTH_BUFFER_BIT);
+		g3d_enable(G3D_DEPTH_TEST);
+	} else {
+		g3d_clear(G3D_COLOR_BUFFER_BIT);
+		g3d_disable(G3D_DEPTH_TEST);
+	}
+
 
 	g3d_matrix_mode(G3D_MODELVIEW);
 	g3d_load_identity();
@@ -147,18 +155,23 @@ static void draw(void)
 
 		draw_bsp(&torus_bsp, vdir[0], vdir[1], vdir[2]);
 	} else {
-		//zsort_mesh(&torus);
+		if(!use_zbuf) {
+			zsort_mesh(&torus);
+		}
 		draw_mesh(&torus);
 	}
 
+	/* show zbuffer */
 	/*{
 		int i;
 		for(i=0; i<FB_WIDTH*FB_HEIGHT; i++) {
 			unsigned int z = pfill_zbuf[i];
-			fb_pixels[i] = z;
+			fb_pixels[i] = (z >> 5) & 0x7e0;
 		}
 	}*/
 
+	cs_dputs(fb_pixels, 140, 0, use_zbuf ? "zbuffer" : "zsort");
+
 	/*draw_mesh(&cube);*/
 	swap_buffers(fb_pixels);
 }
@@ -227,6 +240,11 @@ static void keypress(int key)
 		use_bsp = !use_bsp;
 		printf("drawing with %s\n", use_bsp ? "BSP tree" : "z-sorting");
 		break;
+
+	case 'z':
+		use_zbuf = !use_zbuf;
+		printf("Z-buffer %s\n", use_zbuf ? "on" : "off");
+		break;
 	}
 }
 
-- 
1.7.10.4