From: John Tsiombikas <nuclear@member.fsf.org>
Date: Sun, 16 Oct 2022 02:33:01 +0000 (+0300)
Subject: rotation
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=voxscape;a=commitdiff_plain;h=365156a5f69ea9a4dd54a2a86e5dbc20d05621d7

rotation
---

diff --git a/Makefile b/Makefile
index 2859bb3..40100fc 100644
--- a/Makefile
+++ b/Makefile
@@ -6,8 +6,9 @@ bin = voxscape
 warn = -pedantic -Wall
 #opt = -O3
 dbg = -g
+incdir = -I.
 
-CFLAGS = $(warn) $(opt) $(dbg) -MMD
+CFLAGS = $(warn) $(opt) $(dbg) -MMD $(incdir)
 LDFLAGS = -lGL -lglut -lm -limago
 
 $(bin): $(obj)
diff --git a/src/lut.c b/src/lut.c
new file mode 100644
index 0000000..895d84f
--- /dev/null
+++ b/src/lut.c
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <math.h>
+#include "lut.h"
+
+/*#include "sintab.h"*/
+
+#undef WRITE_C
+
+#ifndef SINTAB_DATA_H_
+int32_t sintab[SINTAB_SIZE];
+#endif
+
+void init_lut(void)
+{
+#ifndef SINTAB_DATA_H_
+	int i;
+	float t, theta;
+
+#ifdef WRITE_C
+	int col = 4;
+	FILE *fp = fopen("sintab.h", "wb");
+	if(fp) {
+		fprintf(fp, "#ifndef SINTAB_DATA_H_\n");
+		fprintf(fp, "#define SINTAB_DATA_H_\n\n");
+		fprintf(fp, "int32_t sintab[] = {\n\t");
+	}
+#endif
+
+	for(i=0; i<SINTAB_SIZE; i++) {
+		t = (float)i / SINTAB_SIZE;
+		theta = t * (M_PI * 2);
+		sintab[i] = (int32_t)(sin(theta) * 65536.0f);
+#ifdef WRITE_C
+		if(fp) {
+			col += fprintf(fp, "%ld", (long)sintab[i]);
+			if(i < SINTAB_SIZE - 1) {
+				if(col >= 72) {
+					fprintf(fp, ",\n\t");
+					col = 4;
+				} else {
+					col += fprintf(fp, ", ");
+				}
+			} else {
+				fprintf(fp, "\n");
+			}
+		}
+#endif
+	}
+
+#ifdef WRITE_C
+	if(fp) {
+		fprintf(fp, "};\n\n");
+		fprintf(fp, "#endif\t/* SINTAB_DATA_H_ */\n");
+		fclose(fp);
+	}
+#endif
+#endif	/* !defined SINTAB_DATA_H_ */
+}
diff --git a/src/lut.h b/src/lut.h
new file mode 100644
index 0000000..4e77b45
--- /dev/null
+++ b/src/lut.h
@@ -0,0 +1,20 @@
+#ifndef LUT_H_
+#define LUT_H_
+
+#include <stdint.h>
+
+#define SINTAB_BITS	9
+#define SINTAB_SIZE	(1 << SINTAB_BITS)
+
+#define SIN(angle) \
+	(sintab[((angle) >> (16 - SINTAB_BITS)) & (SINTAB_SIZE - 1)])
+
+#define COS(angle) \
+	(sintab[(((angle) >> (16 - SINTAB_BITS)) + (SINTAB_SIZE / 4)) & (SINTAB_SIZE - 1)])
+
+
+extern int32_t sintab[SINTAB_SIZE];
+
+void init_lut(void);
+
+#endif	/* LUT_H_ */
diff --git a/src/main.c b/src/main.c
index c2192ee..f690a0e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -6,12 +6,15 @@
 #include <GL/glut.h>
 #include "glfb.h"
 #include "voxscape.h"
+#include "lut.h"
 
 enum {
-	INP_FWD		= 1,
-	INP_BACK	= 2,
-	INP_LEFT	= 4,
-	INP_RIGHT	= 8
+	INP_FWD		= 0x01,
+	INP_BACK	= 0x02,
+	INP_LEFT	= 0x04,
+	INP_RIGHT	= 0x08,
+	INP_LTURN	= 0x10,
+	INP_RTURN	= 0x20
 };
 
 int init(void);
@@ -29,7 +32,7 @@ int win_width, win_height;
 unsigned int fb[FB_W * FB_H];
 
 unsigned int input;
-int32_t pos[2];
+int32_t pos[2], angle;// = 0x4000;
 
 struct voxscape *vox;
 
@@ -59,6 +62,8 @@ int main(int argc, char **argv)
 
 int init(void)
 {
+	init_lut();
+
 	pos[0] = 512 << 16;
 	pos[1] = 512 << 16;
 
@@ -67,7 +72,7 @@ int init(void)
 	}
 	vox_framebuf(vox, FB_W, FB_H, fb);
 	vox_proj(vox, 45, 1, 200);
-	vox_view(vox, pos[0], pos[1], 0);
+	vox_view(vox, pos[0], pos[1], angle);
 
 	glfb_setup(FB_W, FB_H, GLFB_RGBA32, FB_W * 4);
 	return 0;
@@ -79,6 +84,8 @@ void cleanup(void)
 }
 
 #define WALK_SPEED	0x40000
+#define TURN_SPEED	0x100
+
 void update(void)
 {
 	if(input & INP_FWD) pos[1] += WALK_SPEED;
@@ -86,7 +93,10 @@ void update(void)
 	if(input & INP_LEFT) pos[0] -= WALK_SPEED;
 	if(input & INP_RIGHT) pos[0] += WALK_SPEED;
 
-	vox_view(vox, pos[0], pos[1], 0);
+	if(input & INP_LTURN) angle += TURN_SPEED;
+	if(input & INP_RTURN) angle -= TURN_SPEED;
+
+	vox_view(vox, pos[0], pos[1], angle);
 }
 
 void display(void)
@@ -136,6 +146,12 @@ void keyb(unsigned char key, int x, int y)
 	case 'd':
 		input |= INP_RIGHT;
 		break;
+	case 'q':
+		input |= INP_LTURN;
+		break;
+	case 'e':
+		input |= INP_RTURN;
+		break;
 
 	default:
 		break;
@@ -157,6 +173,12 @@ void keyb_up(unsigned char key, int x, int y)
 	case 'd':
 		input &= ~INP_RIGHT;
 		break;
+	case 'q':
+		input &= ~INP_LTURN;
+		break;
+	case 'e':
+		input &= ~INP_RTURN;
+		break;
 
 	default:
 		break;
diff --git a/src/voxscape.c b/src/voxscape.c
index 28a02bf..0ea8f06 100644
--- a/src/voxscape.c
+++ b/src/voxscape.c
@@ -6,6 +6,7 @@
 #include <assert.h>
 #include <imago2.h>
 #include "voxscape.h"
+#include "lut.h"
 
 enum {
 	SLICELEN	= 1
@@ -179,17 +180,12 @@ void vox_begin(struct voxscape *vox)
 {
 	int i;
 
-	/*
-	for(i=0; i<vox->fbwidth; i++) {
-		vox->coltop[i] = vox->fbheight;
-	}
-	*/
 	memset(vox->coltop, 0, vox->fbwidth * sizeof *vox->coltop);
 
 	if(!(vox->valid & SLICELEN)) {
 		float theta = (float)vox->fov * M_PI / 360.0f;	/* half angle */
 		for(i=0; i<vox->nslices; i++) {
-			vox->slicelen[i] = (int32_t)((vox->znear + i) * tan(theta) * 10.0f * 65536.0f);
+			vox->slicelen[i] = (int32_t)((vox->znear + i) * tan(theta) * 4.0f * 65536.0f);
 		}
 		vox->valid |= SLICELEN;
 	}
@@ -197,22 +193,25 @@ void vox_begin(struct voxscape *vox)
 
 void vox_render_slice(struct voxscape *vox, int n)
 {
-	int i, j, tx, ty, hval, colstart, colheight;
-	int32_t x, y, len, xstep;
+	int i, j, tx, ty, hval, colstart, colheight, z;
+	int32_t x, y, len, xstep, ystep;
 	uint32_t color;
 	uint32_t *fbptr;
 
-	len = vox->slicelen[n];
-	xstep = len / vox->fbwidth;
+	z = vox->znear + n;
+
+	len = vox->slicelen[n] >> 8;
+	xstep = ((COS(vox->angle) >> 8) * len) / vox->fbwidth;
+	ystep = ((SIN(vox->angle) >> 8) * len) / vox->fbwidth;
 
-	x = vox->x - xstep * (vox->fbwidth >> 1);
-	y = vox->y + ((vox->znear + n) << 16);
+	x = vox->x - SIN(vox->angle) * z - xstep * (vox->fbwidth >> 1);
+	y = vox->y + COS(vox->angle) * z - ystep * (vox->fbwidth >> 1);
 	for(i=0; i<vox->fbwidth; i++) {
 		tx = (x >> 16) & vox->xmask;
 		ty = (y >> 16) & vox->ymask;
 
 		hval = vox->height[(ty << vox->xshift) + tx] - 80;
-		hval = hval * 80 / (vox->znear + n) + 250;
+		hval = hval * 160 / (vox->znear + n) + 250;
 		if(hval > vox->fbheight) hval = vox->fbheight;
 		if(hval > vox->coltop[i]) {
 			color = vox->color[(ty << vox->xshift) + tx];
@@ -228,6 +227,7 @@ void vox_render_slice(struct voxscape *vox, int n)
 		}
 
 		x += xstep;
+		y += ystep;
 	}
 }