Triangle fill.

5 files changed, 178 insertions, 17 deletions

diff --git a/3de.c b/3de.c
index 6bf9e33..8af3d18 100644
--- a/3de.c
+++ b/3de.c
@@ -20,29 +20,42 @@ void draw_torus(Renderer* r, Colour c) {
 	static int a = 0;
 	const int pc = sizeof torus_points / sizeof *torus_points;
 	int asp = (r->clip.w << fbits) / r->clip.h;
-	int p[4] = { 0, 0, 5 << fbits, f1 };
-	int i;
+	int p[4 * 3] = { 0, 0, 5 << fbits, f1, 0, 0, 0, f1, 0, 0, 0, f1 }, * wp;
+	int i, j;
 	mtx_push_trans(p);
 	mtx_push_rot_x(a);
 	mtx_push_rot_y(a);
 	mtx_push_rot_z(a);
-	for (i = 0; i < pc; i += 3) {
-		vec_cpy(p, &torus_points[i], 3);
-		mtx_apply(mtx_peek(), p);
-		persp(p, asp);
-		ndc2clip((int*)&r->clip, p);
-		ren_point(r, c, p[0], p[1]);
+	for (i = 0; i < pc; i += 9) {
+		for (j = 0; j < 3; j++) {
+			wp = &p[j * 4];
+			vec_cpy(wp, &torus_points[i + j * 3], 3);
+			mtx_apply(mtx_peek(), wp);
+			persp(wp, asp);
+			ndc2clip((int*)&r->clip, wp);
+		}
+		ren_tri(r, c, &p[0], &p[4], &p[8], tri_mode_flat);
 	}
 	mtx_popn(4);
 	a += 3;
 }
 
+void draw_tri(Renderer* r, Colour c, int x, int y) {
+	int v0[] = { 100, 100 };
+	int v1[] = { 0,   0 };
+	int v2[] = { 150, 300 };
+	v1[0] = x;
+	v1[1] = y;
+	ren_tri(r, c, v0, v1, v2, tri_mode_flat);
+}
+
 int entrypoint(int argc, const char** argv, Arena* a) {
 	App* app;
-	Renderer r;
+	Renderer r = { 0 };
 	Heap h;
 	FPS f;
 	char buf[32];
+	int* depth = 0;
 	Colour blue = make_aliceblue();
 	(void)argc;
 	(void)argv;
@@ -55,12 +68,18 @@ int entrypoint(int argc, const char** argv, Arena* a) {
 	app = new_app(&h, 640, 480, "3D Engine");
 	if (!app) return app->err;
 	init_fps(&f, 20);
+	depth = heap_alloc(&h, 3000 * 3000 * sizeof *depth);
+	if (!depth) {
+		print_err("Out of memory.\n");
+		return error_out_of_memory;
+	}
 	while (app->o) {
 		fps_begin(&f);
 		while (f.now >= f.next) {
 			app_begin(app);
-			ren_begin(&r, app->fb, app->w, app->h);
+			ren_begin(&r, app->fb, depth, app->w, app->h);
 				ren_clear(&r);
+				ren_cleard(&r, f1 * 300);
 				sprintf(buf, "FPS: %d", app->fps);
 				ren_text(&r, blue, 3, 3,  buf);
 				sprintf(buf, "CAP: %d", f.fps);
diff --git a/config.h b/config.h
index 96094dd..31e98f4 100644
--- a/config.h
+++ b/config.h
@@ -1,7 +1,7 @@
 #ifndef config_h
 #define config_h
 
-#define memory_size (1024 * 1024 * 32)
-#define app_memory_size (1024 * 1024 * 16)
+#define memory_size (1024 * 1024 * 128)
+#define app_memory_size (1024 * 1024 * 64)
 
 #endif
diff --git a/maths.c b/maths.c
index db11491..74d682d 100644
--- a/maths.c
+++ b/maths.c
@@ -232,7 +232,6 @@ void persp(int* v, int asp) {
 	v[2] += !v[2];
 	v[0] = ((v[0] << fbits) / v[2]);
 	v[1] = ((v[1] << fbits) / v[2]) * asp >> fbits;
-	v[2] = f1;
 }
 
 void ndc2clip(int* c, int* p) {
diff --git a/render.c b/render.c
index 74da997..5949ee9 100644
--- a/render.c
+++ b/render.c
@@ -1,3 +1,5 @@
+#include "maths.h"
+#include "plat.h"
 #include "render.h"
 
 static int font_w = 960;
@@ -121,10 +123,11 @@ Colour blend_mod(Colour dst, Colour src, Colour mod) {
 }
 
 
-void ren_begin(Renderer* r, Colour* t, int w, int h) {
+void ren_begin(Renderer* r, Colour* t, int* d, int w, int h) {
 	r->t = t;
 	r->w = w;
 	r->h = h;
+	r->d = d;
 	r->clip.x = 0;
 	r->clip.y = 0;
 	r->clip.w = w;
@@ -149,6 +152,13 @@ void ren_clearc(Renderer* r, Colour c) {
 		*d = c;
 }
 
+void ren_cleard(Renderer* r, int depth) {
+	int* d = r->d;
+	int i = 0, e = r->w * r->h;
+	for (i = 0; i < e; i++, d++)
+		*d = depth;
+}
+
 void ren_clip(Renderer* r, const Rect* c) {
 	r->clip = *c;
 }
@@ -183,8 +193,8 @@ void ren_char(
 	for (j = re.y, l = sub.y; j < ey; j++, l++) {
 		for (i = re.x, k = sub.x; i < ex; i++, k++) {
 			int si = k + l * font_w;
-			unsigned bits = font_data[si / 32];
-			int bit = bits & (1 << si % 32);
+			unsigned bits = font_data[si >> 5];
+			int bit = bits & 1 << (si & 0x1f);
 			if (bit)
 				*dst = blend(*dst, c);
 			dst++;
@@ -205,3 +215,120 @@ void ren_text(
 		ren_char(r, c, x, y, *s);
 }
 
+#define max_tri_ec 2
+
+void swap_vert(int* a, int* b, int ec) {
+	int t, i;
+	for (i = 0; i < ec; i++) {
+		t = a[i];
+		a[i] = b[i];
+		b[i] = t;
+	}
+}
+
+int tri_hand(int* v0, int* v1, int* v2) {
+	return
+		(v1[0] - v0[0]) * (v2[1] - v0[1]) -
+		(v2[0] - v0[0]) * (v1[1] - v0[1]) > 0;
+}
+
+void ren_tri(
+	Renderer* r,
+	Colour c,
+	int* v0,
+	int* v1,
+	int* v2,
+	Tri_Mode mode
+) {
+	int ec, sx, ex, x, y, me, ms, e, ha;
+	int sb = 0, * d;
+	switch (mode) {
+		case tri_mode_flat:
+			ec = 2;
+			break;
+		default: assert(0);
+	}
+	if (v0[1] > v1[1])
+		swap_vert(v0, v1, ec);
+	if (v1[1] > v2[1])
+		swap_vert(v1, v2, ec);
+	if (v0[1] > v1[1])
+		swap_vert(v0, v1, ec);
+	ha = tri_hand(v0, v1, v2);
+	sb = v1[1] == v2[1];
+	if (v0[1] == v1[1]) goto rb;
+	if (ha) {
+		ms =
+			((v2[0] - v0[0]) << fbits) /
+			(v2[1] - v0[1]);
+		me =
+			((v1[0] - v0[0]) << fbits) /
+			(v1[1] - v0[1]);
+		sx = v0[0] << fbits;
+		ex = v0[0] << fbits;
+	} else {
+		ms =
+			((v1[0] - v0[0]) << fbits) /
+			(v1[1] - v0[1]);
+		me =
+			((v2[0] - v0[0]) << fbits) /
+			(v2[1] - v0[1]);
+		sx = v0[0] << fbits;
+		ex = v0[0] << fbits;
+	}
+	for (
+		y  = v0[1];
+		y <= v1[1];
+		y++, sx += ms, ex += me
+	) for (
+			x = sx >> fbits,
+			e = ex >> fbits;
+			x < e;
+			x++
+		) {
+			d = &r->d[x + y * r->w];
+			if (*d > v0[2]) {
+				*d = v0[2];
+				r->t[x + y * r->w] = c;
+			}
+		}
+rb:
+	if (sb) return;
+	if (ha) {
+		ms = ((v2[0] - v0[0]) << fbits) /
+			(v2[1] - v0[1]);
+		me =
+			((v2[0] - v1[0]) << fbits) /
+			(v2[1] - v1[1]);
+		sx =
+			(v0[0] << fbits) + (v1[1] - v0[1]) * ms + 1;
+		ex = v1[0] << fbits;
+	} else {
+		me =
+			((v2[0] - v0[0]) << fbits) /
+			(v2[1] - v0[1]);
+		ms = 
+			((v2[0] - v1[0]) << fbits) /
+			(v2[1] - v1[1]);
+		sx = v1[0] << fbits;
+		ex =
+			(v0[0] << fbits) + (v1[1] - v0[1]) * me + 1;
+	}
+	for (
+		y = v1[1];
+		y <= v2[1];
+		y++, sx += ms, ex += me
+	) for (
+			x = sx >> fbits,
+			e = ex >> fbits;
+			x < e;
+			x++
+		) {
+			d = &r->d[x + y * r->w];
+			if (*d > v0[2]) {
+				*d = v0[2];
+				r->t[x + y * r->w] = c;
+			}
+		}
+}
+
diff --git a/render.h b/render.h
index 36bafe4..887cffa 100644
--- a/render.h
+++ b/render.h
@@ -20,14 +20,16 @@ Colour blend_mod(Colour dst, Colour src, Colour mod);
 
 typedef struct {
 	Colour* t;
+	int* d;
 	int w, h;
 	Rect clip;
 } Renderer;
 
-void ren_begin(Renderer* r, Colour* t, int w, int h);
+void ren_begin(Renderer* r, Colour* t, int* d, int w, int h);
 void ren_end(Renderer* r);
 void ren_clear(Renderer* r);
 void ren_clearc(Renderer* r, Colour c);
+void ren_cleard(Renderer* r, int depth);
 void ren_clip(Renderer* r, const Rect* c);
 void ren_point(Renderer* r, Colour c, int x, int y);
 void ren_char(
@@ -44,5 +46,19 @@ void ren_text(
 	int y,
 	const char* t
 );
+typedef enum {
+	tri_mode_flat,
+	tri_mode_textured,
+	tri_mode_lit,
+	tri_mode_textured_lit
+} Tri_Mode;
+void ren_tri(
+	Renderer* r,
+	Colour c,
+	int* v0,
+	int* v1,
+	int* v2,
+	Tri_Mode mode
+);
 
 #endif