From: John Tsiombikas <nuclear@member.fsf.org>
Date: Tue, 16 Mar 2021 11:52:13 +0000 (+0200)
Subject: axis gizmo
X-Git-Tag: v1.0~3
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=gba_blender;a=commitdiff_plain;h=70c4f810480b6e814bdc18ad8b9384747a717058

axis gizmo
---

diff --git a/src/main.c b/src/main.c
index 2110b9a..9f42c02 100644
--- a/src/main.c
+++ b/src/main.c
@@ -32,9 +32,17 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 enum {
 	SIDX_DEL0, SIDX_DEL1, SIDX_DEL2,
 	SIDX_TIME,
-	SIDX_ICONS_BASE
+	SIDX_ICON_ZOOM,
+	SIDX_ICON_PAN,
+	SIDX_ICON_ORBIT,
+	SIDX_ICON_X,
+	SIDX_ICON_Y,
+	SIDX_ICON_Z,
+	SIDX_DIRTY,
 };
 
+#define SIDX_ICONS_BASE		SIDX_ICON_ZOOM
+
 #define SNAM_START	512
 enum {
 	SNAM_DEL0		= SNAM_START,
@@ -45,7 +53,8 @@ enum {
 	SNAM_ICON_ORBIT	= SNAM_START + 32 * 4 + 24,	/* for tiles down, 24 across */
 	SNAM_ICON_X		= SNAM_START + 32 * 8 + 26,
 	SNAM_ICON_Y		= SNAM_ICON_X + 2,
-	SNAM_ICON_Z		= SNAM_ICON_Y + 2
+	SNAM_ICON_Z		= SNAM_ICON_Y + 2,
+	SNAM_DIRTY		= SNAM_ICON_ORBIT + 4
 };
 
 #define MENU_HEIGHT		17
@@ -53,6 +62,7 @@ enum {
 #define VP_HEIGHT		(160 - MENU_HEIGHT - TRACK_HEIGHT)
 
 static void handle_keys(void);
+static void upd_rotation(void);
 static void show_msgbox(int en);
 
 extern struct { unsigned char r, g, b; } bgimg_cmap[];
@@ -61,9 +71,11 @@ extern unsigned char bgimg_pixels[];
 static int32_t cam_theta = 0x10000, cam_phi = -0x8000;
 
 static int show_obj = 1, show_del;
+static int32_t rot_matrix[16];
 
 #define AXIS0	0x10000
 #define AXIS1	0x80000
+#define AXIS3	0x2c000
 
 static struct xvertex gridaxes[] = {
 	{AXIS0, 0, 0,	0, 0, 0, 92},
@@ -85,13 +97,23 @@ static struct xvertex gridaxes[] = {
 	{0, 0, -AXIS1,	0, 0, 0, 93},
 };
 
-#define MAX_SIDX	8
+static struct xvertex small_axes[] = {
+	{0, 0, 0,		0, 0, 0, 92},
+	{AXIS3, 0, 0,	0, 0, 0, 92},
+	{0, 0, 0,		0, 0, 0, 93},
+	{0, 0, AXIS3,	0, 0, 0, 93},
+	{0, 0, 0,		0, 0, 0, 94},
+	{0, AXIS3, 0,	0, 0, 0, 94}
+};
+
+#define MAX_SIDX	16
 static uint16_t oam[4 * MAX_SIDX];
 
 
 int main(void)
 {
 	int i;
+	int x, y;
 	unsigned int nframes = 0, backbuf;
 	uint16_t *cptr;
 	unsigned char r, g, b;
@@ -127,14 +149,16 @@ int main(void)
 	REG_BLDCNT = BLDCNT_ALPHA | BLDCNT_B_BG2;
 	REG_BLDALPHA = 0x040c;
 
-	set_sprite(oam, SIDX_ICONS_BASE, SNAM_ICON_ZOOM, 213, 57, 4, SPR_SZ32);
-	set_sprite(oam, SIDX_ICONS_BASE + 1, SNAM_ICON_PAN, 213, 81, 4, SPR_SZ32);
-	set_sprite(oam, SIDX_ICONS_BASE + 2, SNAM_ICON_ORBIT, 213, 103, 4, SPR_SZ32);
+	set_sprite(oam, SIDX_ICONS_BASE, SNAM_ICON_ZOOM, 213, 57, 4, SPR_SZ32 | SPR_BLEND);
+	set_sprite(oam, SIDX_ICONS_BASE + 1, SNAM_ICON_PAN, 213, 81, 4, SPR_SZ32 | SPR_BLEND);
+	set_sprite(oam, SIDX_ICONS_BASE + 2, SNAM_ICON_ORBIT, 213, 103, 4, SPR_SZ32 | SPR_BLEND);
+	set_sprite(oam, SIDX_DIRTY, SNAM_DIRTY, 192, 9, 4, SPR_SZ16 | SPR_HRECT);
 
 	xgl_init();
-	xgl_viewport(0, 0, 240, VP_HEIGHT);
 	xgl_enable(XGL_LIGHTING);
 
+	upd_rotation();
+
 	key_repeat(75, 75, KEY_LEFT | KEY_RIGHT | KEY_DOWN | KEY_UP);
 
 	/* every vblank, copy the shadow OAM automatically */
@@ -148,13 +172,12 @@ int main(void)
 
 		fb = fbptr[backbuf] + 240 * MENU_HEIGHT;
 		polyfill_framebuffer(fb, 240, VP_HEIGHT);
-		//memset(fb, 14, 240 * VP_HEIGHT);
 		dma_fill16(3, fb, 0x0e0e, 240 * VP_HEIGHT / 2);
 
+		xgl_viewport(0, 0, 240, VP_HEIGHT);
 		xgl_load_identity();
 		xgl_translate(0, 0, 8 << 16);
-		xgl_rotate_x(cam_phi);
-		xgl_rotate_y(cam_theta);
+		xgl_mult_matrix(rot_matrix);
 
 		if(show_obj) {
 			if(cam_theta < X_PI) {
@@ -186,6 +209,17 @@ int main(void)
 			xgl_draw(XGL_LINES, gridaxes + 8, 8);
 		}
 
+		/* small axes */
+		xgl_viewport(176, 2, 64, 32);
+		xgl_draw(XGL_LINES, small_axes, 6);
+
+		xgl_transform(small_axes + 5, &x, &y);
+		set_sprite(oam, SIDX_ICONS_BASE + 3, SNAM_ICON_Z, x - 8, y + 8, 3, SPR_SZ16);
+		xgl_transform(small_axes + 1, &x, &y);
+		set_sprite(oam, SIDX_ICONS_BASE + 4, SNAM_ICON_X, x - 8, y + 8, 1, SPR_SZ16);
+		xgl_transform(small_axes + 3, &x, &y);
+		set_sprite(oam, SIDX_ICONS_BASE + 5, SNAM_ICON_Y, x - 8, y + 8, 2, SPR_SZ16);
+
 		wait_vblank();
 		present(backbuf);
 		dma_copy16(3, (void*)OAM_ADDR, oam, sizeof oam / 2, 0);
@@ -201,18 +235,22 @@ static void handle_keys(void)
 	if(KEYPRESS(KEY_UP)) {
 		cam_phi += 0x2000;
 		if(cam_phi > X_HPI) cam_phi = X_HPI;
+		upd_rotation();
 	}
 	if(KEYPRESS(KEY_DOWN)) {
 		cam_phi -= 0x2000;
 		if(cam_phi < -X_HPI) cam_phi = -X_HPI;
+		upd_rotation();
 	}
 	if(KEYPRESS(KEY_LEFT)) {
 		cam_theta += 0x2000;
 		if(cam_theta > X_2PI) cam_theta -= X_2PI;
+		upd_rotation();
 	}
 	if(KEYPRESS(KEY_RIGHT)) {
 		cam_theta -= 0x2000;
 		if(cam_theta < 0) cam_theta += X_2PI;
+		upd_rotation();
 	}
 	if(KEYPRESS(KEY_RT)) {
 		if(++show_obj > 2) show_obj = 0;
@@ -238,6 +276,14 @@ static void handle_keys(void)
 	}
 }
 
+static void upd_rotation(void)
+{
+	xgl_load_identity();
+	xgl_rotate_x(cam_phi);
+	xgl_rotate_y(cam_theta);
+	xgl_get_matrix(rot_matrix);
+}
+
 static void show_msgbox(int en)
 {
 	int i;
diff --git a/src/sprites.h b/src/sprites.h
index 3712aba..f1b9b30 100644
--- a/src/sprites.h
+++ b/src/sprites.h
@@ -36,6 +36,7 @@ enum {
 	SPR_SZ32	= 0x800000,
 	SPR_SZ64	= 0xc00000
 };
+#define SPR_SZ8		0
 #define SPR_ROTSCL_PARAM(x)	((unsigned int)(x) << 17)
 #define SPR_PRIO(x)			((unsigned int)(x) & 3)
 
diff --git a/src/xgl.c b/src/xgl.c
index 4880aba..2632473 100644
--- a/src/xgl.c
+++ b/src/xgl.c
@@ -74,7 +74,7 @@ void xgl_pop_matrix(void)
 	if(mtop > 0) mtop--;
 }
 
-static const int32_t id[] = {
+static int32_t id[] = {
 	0x10000, 0, 0, 0,
 	0, 0x10000, 0, 0,
 	0, 0, 0x10000, 0,
@@ -83,7 +83,7 @@ static const int32_t id[] = {
 
 void xgl_load_identity(void)
 {
-	xgl_load_matrix(id);
+	memcpy(mat[mtop], id, sizeof mat[0]);
 }
 
 void xgl_load_matrix(const int32_t *m)
@@ -91,6 +91,11 @@ void xgl_load_matrix(const int32_t *m)
 	memcpy(mat[mtop], m, sizeof mat[0]);
 }
 
+void xgl_get_matrix(int32_t *m)
+{
+	memcpy(m, mat[mtop], sizeof mat[0]);
+}
+
 #define M(i,j)	(((i) << 2) + (j))
 #define XMUL(a, b)	(((a) >> 8) * ((b) >> 8))
 void xgl_mult_matrix(const int32_t *m2)
@@ -243,6 +248,19 @@ void xgl_draw(int prim, const struct xvertex *varr, int vcount)
 	}
 }
 
+void xgl_transform(const struct xvertex *vin, int *x, int *y)
+{
+	struct xvertex v;
+	xform(&v, vin, mat[mtop]);
+
+	v.x = (v.x << 1) / (v.z >> 8);	/* assume aspect: ~2 */
+	v.y = (v.y << 2) / (v.z >> 8);	/* the shift is * PROJ_D */
+	/* projection result is 24.8 */
+	/* viewport */
+	*x = ((((v.x + 0x100) >> 1) * vp[2]) >> 8) + vp[0];
+	*y = ((((0x100 - v.y) >> 1) * vp[3]) >> 8) + vp[1];
+}
+
 static void draw_ptlines(int prim, const struct xvertex *varr, int vcount)
 {
 	int i;
diff --git a/src/xgl.h b/src/xgl.h
index c15231e..6076073 100644
--- a/src/xgl.h
+++ b/src/xgl.h
@@ -51,6 +51,7 @@ void xgl_push_matrix(void);
 void xgl_pop_matrix(void);
 void xgl_load_identity(void);
 void xgl_load_matrix(const int32_t *m);
+void xgl_get_matrix(int32_t *m);
 void xgl_mult_matrix(const int32_t *m);
 
 void xgl_translate(int32_t x, int32_t y, int32_t z);
@@ -60,5 +61,6 @@ void xgl_rotate_z(int32_t angle);
 void xgl_scale(int32_t x, int32_t y, int32_t z);
 
 void xgl_draw(int prim, const struct xvertex *varr, int vcount);
+void xgl_transform(const struct xvertex *vin, int *x, int *y);
 
 #endif	/* XGL_H_ */