From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Tue, 6 Sep 2016 22:45:52 +0000 (+0300)
Subject: wrote most of the 3d pipeline stuff
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=commitdiff_plain;ds=inline;h=d1a2007e191d68b104e436d1817eafcc99ae21dd;p=dosdemo

wrote most of the 3d pipeline stuff
---

diff --git a/src/3dgfx.c b/src/3dgfx.c
index e7aabc2..5cf3c42 100644
--- a/src/3dgfx.c
+++ b/src/3dgfx.c
@@ -1,5 +1,8 @@
+#include <stdio.h>
+#include <math.h>
 #include <string.h>
 #include "3dgfx.h"
+#include "polyfill.h"
 
 #define STACK_SIZE	8
 typedef float g3d_matrix[16];
@@ -14,7 +17,17 @@ struct g3d_state {
 	void *pixels;
 };
 
+static void xform4_vec3(const float *mat, float *vec);
+static void xform3_vec3(const float *mat, float *vec);
+static void proc_vertex(struct pvertex *res, const struct g3d_vertex *vert, int space);
+
 static struct g3d_state st;
+static const float idmat[] = {
+	1, 0, 0, 0,
+	0, 1, 0, 0,
+	0, 0, 1, 0,
+	0, 0, 0, 1
+};
 
 void g3d_init(void)
 {
@@ -57,6 +70,8 @@ unsigned int g3d_getopt(unsigned int mask)
 void g3d_set_matrix(int which, const float *m)
 {
 	int top = st.mtop[which];
+
+	if(!m) m = idmat;
 	memcpy(st.mat[which][top], m, 16 * sizeof(float));
 }
 
@@ -78,4 +93,229 @@ void g3d_mult_matrix(int which, const float *m2)
 		}
 	}
 }
-/* TODO continue ... */
+
+void g3d_push_matrix(int which)
+{
+	int top = st.mtop[which];
+	if(top >= G3D_NUM_MATRICES) {
+		fprintf(stderr, "g3d_push_matrix overflow\n");
+		return;
+	}
+	memcpy(st.mat[which][top + 1], st.mat[which][top], 16 * sizeof(float));
+	st.mtop[which] = top + 1;;
+}
+
+void g3d_pop_matrix(int which)
+{
+	if(st.mtop[which] <= 0) {
+		fprintf(stderr, "g3d_pop_matrix underflow\n");
+		return;
+	}
+	--st.mtop[which];
+}
+
+void g3d_translate(int which, float x, float y, float z)
+{
+	float m[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};
+	m[12] = x;
+	m[13] = y;
+	m[14] = z;
+	g3d_mult_matrix(which, m);
+}
+
+void g3d_rotate(int which, float deg, float x, float y, float z)
+{
+	float m[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+	float angle = M_PI * deg / 180.0f;
+	float sina = sin(angle);
+	float cosa = cos(angle);
+	float one_minus_cosa = 1.0f - cosa;
+	float nxsq = x * x;
+	float nysq = y * y;
+	float nzsq = z * z;
+
+	m[0] = nxsq + (1.0f - nxsq) * cosa;
+	m[4] = x * y * one_minus_cosa - z * sina;
+	m[8] = x * z * one_minus_cosa + y * sina;
+	m[1] = x * y * one_minus_cosa + z * sina;
+	m[5] = nysq + (1.0 - nysq) * cosa;
+	m[9] = y * z * one_minus_cosa - x * sina;
+	m[2] = x * z * one_minus_cosa - y * sina;
+	m[6] = y * z * one_minus_cosa + x * sina;
+	m[10] = nzsq + (1.0 - nzsq) * cosa;
+
+	g3d_mult_matrix(which, m);
+}
+
+void g3d_scale(int which, float x, float y, float z)
+{
+	float m[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+	m[0] = x;
+	m[5] = y;
+	m[10] = z;
+	g3d_mult_matrix(which, m);
+}
+
+void g3d_ortho(int which, float left, float right, float bottom, float top, float znear, float zfar)
+{
+	float m[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+	float dx = right - left;
+	float dy = top - bottom;
+	float dz = zfar - znear;
+
+	m[0] = 2.0 / dx;
+	m[5] = 2.0 / dy;
+	m[10] = -2.0 / dz;
+	m[12] = -(right + left) / dx;
+	m[13] = -(top + bottom) / dy;
+	m[14] = -(zfar + znear) / dz;
+
+	g3d_mult_matrix(which, m);
+}
+
+void g3d_frustum(int which, float left, float right, float bottom, float top, float nr, float fr)
+{
+	float m[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+	float dx = right - left;
+	float dy = top - bottom;
+	float dz = fr - nr;
+
+	float a = (right + left) / dx;
+	float b = (top + bottom) / dy;
+	float c = -(fr + nr) / dz;
+	float d = -2.0 * fr * nr / dz;
+
+	m[0] = 2.0 * nr / dx;
+	m[5] = 2.0 * nr / dy;
+	m[8] = a;
+	m[9] = b;
+	m[10] = c;
+	m[11] = -1.0f;
+	m[14] = d;
+
+	g3d_mult_matrix(which, m);
+}
+
+void g3d_perspective(int which, float vfov_deg, float aspect, float znear, float zfar)
+{
+	float m[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+	float vfov = M_PI * vfov_deg / 180.0f;
+	float s = 1.0f / tan(vfov * 0.5f);
+	float range = znear - zfar;
+
+	m[0] = s / aspect;
+	m[5] = s;
+	m[10] = (znear + zfar) / range;
+	m[11] = -1.0f;
+	m[14] = 2.0f * znear * zfar / range;
+
+	g3d_mult_matrix(which, m);
+}
+
+void g3d_draw(int prim, int space, const struct g3d_vertex *varr, int varr_size)
+{
+	int i;
+	int vnum = prim; /* primitive vertex counts correspond to the enum values */
+
+	while(varr_size >= vnum) {
+		struct pvertex pv[4];
+
+		for(i=0; i<vnum; i++) {
+			proc_vertex(pv + i, varr++, space);
+		}
+
+		polyfill_wire(pv, vnum);
+
+		varr_size -= vnum;
+	}
+}
+
+static void xform4_vec3(const float *mat, float *vec)
+{
+	float x = mat[0] * vec[0] + mat[4] * vec[1] + mat[8] * vec[2] + mat[12];
+	float y = mat[1] * vec[0] + mat[5] * vec[1] + mat[9] * vec[2] + mat[13];
+	float z = mat[2] * vec[0] + mat[6] * vec[1] + mat[10] * vec[2] + mat[14];
+	float w = mat[3] * vec[0] + mat[7] * vec[1] + mat[11] * vec[2] + mat[15];
+
+	vec[0] = x;
+	vec[1] = y;
+	vec[2] = z;
+	vec[3] = w;
+}
+
+static void xform3_vec3(const float *mat, float *vec)
+{
+	float x = mat[0] * vec[0] + mat[4] * vec[1] + mat[8] * vec[2];
+	float y = mat[1] * vec[0] + mat[5] * vec[1] + mat[9] * vec[2];
+	float z = mat[2] * vec[0] + mat[6] * vec[1] + mat[10] * vec[2];
+
+	vec[0] = x;
+	vec[1] = y;
+	vec[2] = z;
+}
+
+#define VEC3(v, x, y, z) do { v[0] = x; v[1] = y; v[2] = z; } while(0)
+#define VEC4(v, x, y, z, w) do { v[0] = x; v[1] = y; v[2] = z; v[3] = w; } while(0)
+
+static void proc_vertex(struct pvertex *res, const struct g3d_vertex *vert, int space)
+{
+	float pos[4];
+	float norm[3];
+	float color[3];
+	int mvtop = st.mtop[G3D_MODELVIEW];
+	int ptop = st.mtop[G3D_PROJECTION];
+	g3d_matrix norm_mat;
+
+	VEC4(pos, vert->x, vert->y, vert->z, 1.0f);
+	VEC3(norm, vert->nx, vert->ny, vert->nz);
+
+	switch(space) {
+	case G3D_LOCAL_SPACE:
+		memcpy(norm_mat, st.mat[G3D_MODELVIEW][mvtop], 16 * sizeof(float));
+		norm_mat[12] = norm_mat[13] = norm_mat[14] = 0.0f;
+
+		xform4_vec3(pos, st.mat[G3D_MODELVIEW][mvtop]);
+		xform3_vec3(norm, norm_mat);
+
+	case G3D_VIEW_SPACE:
+		if(st.opt & G3D_LIGHTING) {
+			/* TODO lighting */
+			color[0] = vert->r;
+			color[1] = vert->g;
+			color[2] = vert->b;
+		}
+		xform4_vec3(pos, st.mat[G3D_PROJECTION][ptop]);
+
+	case G3D_CLIP_SPACE:
+		/* TODO clipping */
+		if(pos[3] != 0.0f) {
+			pos[0] /= pos[3];
+			pos[1] /= pos[3];
+			pos[2] /= pos[3];
+		}
+
+	case G3D_SCREEN_SPACE:
+		pos[0] = (pos[0] * 0.5 + 0.5) * (float)st.width;
+		pos[1] = (0.5 - pos[0] * 0.5) * (float)st.height;
+
+	case G3D_PIXEL_SPACE:
+		break;
+	}
+
+	/* convert pos to 24.8 fixed point */
+	res->x = (int32_t)(pos[0] * 256.0f);
+	res->y = (int32_t)(pos[1] * 256.0f);
+
+	/* convert tex coords to 16.16 fixed point */
+	res->u = (int32_t)(vert->u * 65536.0f);
+	res->v = (int32_t)(vert->v * 65536.0f);
+
+	/* pass color through as is */
+	res->r = color[0];
+	res->g = color[1];
+	res->b = color[2];
+}
diff --git a/src/3dgfx.h b/src/3dgfx.h
index a6b3645..a2fa154 100644
--- a/src/3dgfx.h
+++ b/src/3dgfx.h
@@ -28,8 +28,7 @@ enum {
 /* 2nd arg to g3d_draw: which space are input verts in. skips parts of the pipeline */
 enum {
 	G3D_LOCAL_SPACE, /* this being 0 makes a nice default arg. */
-	G3D_WORLD_SPACE, /* ignore world matrix */
-	G3D_VIEW_SPACE,  /* ignore view matrix */
+	G3D_VIEW_SPACE,  /* ignore modelview matrix */
 	G3D_CLIP_SPACE,  /* ignore projection matrix */
 	G3D_SCREEN_SPACE,/* 2D verts, don't divide by w */
 	G3D_PIXEL_SPACE  /* in pixel units, ignore viewport */
@@ -37,8 +36,7 @@ enum {
 
 /* matrix stacks */
 enum {
-	G3D_WORLD,
-	G3D_VIEW,
+	G3D_MODELVIEW,
 	G3D_PROJECTION,
 
 	G3D_NUM_MATRICES
@@ -58,13 +56,13 @@ void g3d_mult_matrix(int which, const float *m);
 void g3d_push_matrix(int which);
 void g3d_pop_matrix(int which);
 
-void g3d_translate(float x, float y, float z);
-void g3d_rotate(float angle, float x, float y, float z);
-void g3d_scale(float x, float y, float z);
-void g3d_ortho(float left, float right, float bottom, float top, float znear, float zfar);
-void g3d_frustum(float left, float right, float bottom, float top, float znear, float zfar);
-void g3d_perspective(float vfov, float aspect, float znear, float zfar);
+void g3d_translate(int which, float x, float y, float z);
+void g3d_rotate(int which, float angle, float x, float y, float z);
+void g3d_scale(int which, float x, float y, float z);
+void g3d_ortho(int which, float left, float right, float bottom, float top, float znear, float zfar);
+void g3d_frustum(int which, float left, float right, float bottom, float top, float znear, float zfar);
+void g3d_perspective(int which, float vfov, float aspect, float znear, float zfar);
 
-void g3d_draw(int prim, int space, const struct g3d_vertex *varr, int num);
+void g3d_draw(int prim, int space, const struct g3d_vertex *varr, int varr_size);
 
 #endif	/* THREEDGFX_H_ */