examples: add icosphere

Makefile

@@ -19,6 +19,7 @@ triangle.elf: $(DEFAULT) arm9/triangle.bin.o
 triangle_rotating.elf: $(DEFAULT) arm9/triangle_rotating.bin.o
 texture.elf: $(DEFAULT) arm9/texture.bin.o
 cube.elf: $(DEFAULT) arm9/cube.bin.o
+icosphere.elf: $(DEFAULT) arm9/icosphere.bin.o
 
 TARGET = arm-none-eabi-
 AARCH = -march=armv4t -mlittle-endian

arm7/arm7.lds

@@ -6,7 +6,7 @@ MEMORY
 }
 SECTIONS
 {
-  . = ORIGIN(ram) + 0x8000;
+  . = ORIGIN(ram) + 0x390000;
 
   .text ALIGN(4) :
   {

arm9/Makefile

@@ -24,6 +24,8 @@ texture.elf: start.o examples/texture.o ../res/hotaru_futaba.data.o ../res/hotar
 
 cube.elf: start.o examples/cube.o ../math/cos_table_fp12.o ../math/cos.o
 
+icosphere.elf: start.o examples/icosphere.o ../math/cos_table_fp12.o ../math/cos.o
+
 CFLAGS += -I../include -I../
 
 include arm9.mk

arm9/examples/cube.c

@@ -163,25 +163,25 @@ void main()
     for (int i = 0; i < 6; i++) {
       io_registers.a.COLOR = face_colors[i];
 
-      struct vertex_position * a = &cube_positions[cube_faces[i].a.position];
+      struct vertex_position * a = &cube_positions[cube_quadrilaterals[i].a.position];
       io_registers.a.VTX_10 = 0
 	| VTX_10__z_coordinate(a->z)
 	| VTX_10__y_coordinate(a->y)
 	| VTX_10__x_coordinate(a->x);
 
-      struct vertex_position * b = &cube_positions[cube_faces[i].b.position];
+      struct vertex_position * b = &cube_positions[cube_quadrilaterals[i].b.position];
       io_registers.a.VTX_10 = 0
 	| VTX_10__z_coordinate(b->z)
 	| VTX_10__y_coordinate(b->y)
 	| VTX_10__x_coordinate(b->x);
 
-      struct vertex_position * c = &cube_positions[cube_faces[i].c.position];
+      struct vertex_position * c = &cube_positions[cube_quadrilaterals[i].c.position];
       io_registers.a.VTX_10 = 0
 	| VTX_10__z_coordinate(c->z)
 	| VTX_10__y_coordinate(c->y)
 	| VTX_10__x_coordinate(c->x);
 
-      struct vertex_position * d = &cube_positions[cube_faces[i].d.position];
+      struct vertex_position * d = &cube_positions[cube_quadrilaterals[i].d.position];
       io_registers.a.VTX_10 = 0
 	| VTX_10__z_coordinate(d->z)
 	| VTX_10__y_coordinate(d->y)

arm9/examples/icosphere.c

@@ -0,0 +1,265 @@
+#include "io_registers.h"
+#include "bits.h"
+
+#include "models/icosphere.h"
+#include "math/math.h"
+
+void main()
+{
+  // power control
+  io_registers.a.POWCNT = 0
+    | POWCNT__lcd_output_destination__a_to_upper__b_to_lower
+    | POWCNT__geometry_engine__enable
+    | POWCNT__rendering_engine__enable
+    | POWCNT__lcd__enable;
+
+  // enable bg0 and 3d graphics
+  io_registers.a.DISPCNT = 0
+    | DISPCNT__display_mode__graphics_display
+    | DISPCNT__bg0__enable
+    | DISPCNT__display_selection_for_bg0__3d_graphics
+    ;
+
+  // disable all 3d effects
+  io_registers.a.DISP3DCNT = 0
+    | DISP3DCNT__clear_image__disable
+    | DISP3DCNT__fog_master__disable
+    | DISP3DCNT__edge_marking__disable
+    | DISP3DCNT__anti_aliasing__disable
+    | DISP3DCNT__alpha_blending__disable
+    | DISP3DCNT__alpha_test__disable
+    | DISP3DCNT__texture_mapping__disable;
+
+  // clear matrix stack status
+  io_registers.a.GXSTAT |= GXSTAT__matrix_stack_status__overflow_or_underflow;
+
+  // load identity matrices
+  io_registers.a.MTX_MODE = MTX_MODE__matrix_mode__projection;
+  io_registers.a.MTX_IDENTITY = 0;
+
+  /*
+  io_registers.a.MTX_SCALE = ((192 << 12) / (256)) / 2;
+  io_registers.a.MTX_SCALE = 0.5 * 4096;
+  io_registers.a.MTX_SCALE = 0.5 * 4096;
+  */
+
+  // load a symmetric perspective matrix, with aspect ratio correction
+  io_registers.a.MTX_LOAD_4X4 = (192 << 12) / 256;
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = 0;
+
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = 1 << 12;
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = 0;
+
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = -(1 << 12);
+
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = 0;
+  io_registers.a.MTX_LOAD_4X4 = -(1 << 12);
+  io_registers.a.MTX_LOAD_4X4 = 0;
+
+  // translate the viewpoint
+  io_registers.a.MTX_TRANS = 0;
+  io_registers.a.MTX_TRANS = 0;
+  io_registers.a.MTX_TRANS = (int)(-2.1 * (float)(1 << 12));
+
+  io_registers.a.MTX_MODE = MTX_MODE__matrix_mode__position;
+  io_registers.a.MTX_IDENTITY = 0;
+
+  io_registers.a.MTX_MODE = MTX_MODE__matrix_mode__position_and_vector;
+  io_registers.a.MTX_IDENTITY = 0;
+
+  // set the 3d clear color to a dark red
+  io_registers.a.CLEAR_COLOR = 0
+    | CLEAR_COLOR__clear_polygon_id(31)
+    | CLEAR_COLOR__alpha_value(31)
+    | CLEAR_COLOR__blue(1)
+    | CLEAR_COLOR__green(1)
+    | CLEAR_COLOR__red(10);
+
+  // set the depth buffer clear value to the maximum value
+  io_registers.a.CLEAR_DEPTH = CLEAR_DEPTH__value(0x7fff);
+
+  // the following polygons are fully opaque; backface culling is
+  // enabled
+  io_registers.a.POLYGON_ATTR = 0
+    | POLYGON_ATTR__alpha_value(31)
+    | POLYGON_ATTR__render_front_surface__enable
+    | POLYGON_ATTR__render_back_surface__enable
+    | POLYGON_ATTR__light_2__enable
+    | POLYGON_ATTR__light_1__enable
+    | POLYGON_ATTR__light_0__enable;
+
+  // the 3d viewport is the entire display area
+  io_registers.a.VIEWPORT = 0
+    | VIEWPORT__y2(191)
+    | VIEWPORT__x2(255)
+    | VIEWPORT__y1(0)
+    | VIEWPORT__x1(0);
+
+  // normalized 45° vector
+  int c = 0.57735 * 512;
+
+  // lighting
+  io_registers.a.LIGHT_VECTOR = 0
+    | LIGHT_VECTOR__light_number(0)
+    | LIGHT_VECTOR__decimal_z(-c)
+    | LIGHT_VECTOR__decimal_y(-c)
+    | LIGHT_VECTOR__decimal_x(-c);
+
+  io_registers.a.LIGHT_VECTOR = 0
+    | LIGHT_VECTOR__light_number(1)
+    | LIGHT_VECTOR__decimal_z(-c)
+    | LIGHT_VECTOR__decimal_y(-c)
+    | LIGHT_VECTOR__decimal_x(c);
+
+  io_registers.a.LIGHT_VECTOR = 0
+    | LIGHT_VECTOR__light_number(2)
+    | LIGHT_VECTOR__decimal_z(-c)
+    | LIGHT_VECTOR__decimal_y(c)
+    | LIGHT_VECTOR__decimal_x(-c);
+
+  io_registers.a.LIGHT_COLOR = 0
+    | LIGHT_COLOR__light_number(0)
+    | LIGHT_COLOR__blue(1)
+    | LIGHT_COLOR__green(1)
+    | LIGHT_COLOR__red(31);
+
+  io_registers.a.LIGHT_COLOR = 0
+    | LIGHT_COLOR__light_number(1)
+    | LIGHT_COLOR__blue(1)
+    | LIGHT_COLOR__green(31)
+    | LIGHT_COLOR__red(1);
+
+  io_registers.a.LIGHT_COLOR = 0
+    | LIGHT_COLOR__light_number(2)
+    | LIGHT_COLOR__blue(31)
+    | LIGHT_COLOR__green(1)
+    | LIGHT_COLOR__red(1);
+
+  // degrees
+  int theta = 0;
+
+  while (1) {
+    // calculate sin/cos for 2d rotation; signed fp20.12 result
+    int cos = cos_fp12(theta);
+    int sin = sin_fp12(theta);
+
+    int cos2 = cos_fp12(theta >> 1);
+    int sin2 = sin_fp12(theta >> 1);
+
+    io_registers.a.MTX_MODE = MTX_MODE__matrix_mode__position_and_vector;
+    // reset position matrix
+    io_registers.a.MTX_IDENTITY = 0;
+
+    // multiply by a z-axis rotation
+    io_registers.a.MTX_MULT_3X3 = cos;
+    io_registers.a.MTX_MULT_3X3 = -sin;
+    io_registers.a.MTX_MULT_3X3 = 0;
+
+    io_registers.a.MTX_MULT_3X3 = sin;
+    io_registers.a.MTX_MULT_3X3 = cos;
+    io_registers.a.MTX_MULT_3X3 = 0;
+
+    io_registers.a.MTX_MULT_3X3 = 0;
+    io_registers.a.MTX_MULT_3X3 = 0;
+    io_registers.a.MTX_MULT_3X3 = 1 << 12;
+
+    // multiply by a y-axis rotation
+    io_registers.a.MTX_MULT_3X3 = cos2;
+    io_registers.a.MTX_MULT_3X3 = 0;
+    io_registers.a.MTX_MULT_3X3 = sin2;
+
+    io_registers.a.MTX_MULT_3X3 = 0;
+    io_registers.a.MTX_MULT_3X3 = 1 << 12;
+    io_registers.a.MTX_MULT_3X3 = 0;
+
+    io_registers.a.MTX_MULT_3X3 = -sin2;
+    io_registers.a.MTX_MULT_3X3 = 0;
+    io_registers.a.MTX_MULT_3X3 = cos2;
+
+    // multiply by a x-axis rotation
+    io_registers.a.MTX_MULT_3X3 = cos2;
+    io_registers.a.MTX_MULT_3X3 = -sin2;
+    io_registers.a.MTX_MULT_3X3 = 0;
+
+    io_registers.a.MTX_MULT_3X3 = sin2;
+    io_registers.a.MTX_MULT_3X3 = cos2;
+    io_registers.a.MTX_MULT_3X3 = 0;
+
+    io_registers.a.MTX_MULT_3X3 = 0;
+    io_registers.a.MTX_MULT_3X3 = 0;
+    io_registers.a.MTX_MULT_3X3 = 1 << 12;
+
+    // cube faces
+
+    io_registers.a.DIF_AMB = 0
+      | DIF_AMB__ambient_blue(1)
+      | DIF_AMB__ambient_green(1)
+      | DIF_AMB__ambient_red(1)
+      | DIF_AMB__diffuse_blue(10)
+      | DIF_AMB__diffuse_green(10)
+      | DIF_AMB__diffuse_red(10);
+
+    io_registers.a.SPE_EMI = 0
+      | SPE_EMI__specular_blue(30)
+      | SPE_EMI__specular_green(30)
+      | SPE_EMI__specular_red(30);
+
+    // the following vertices are a triangles
+    io_registers.a.BEGIN_VTXS = BEGIN_VTXS__type__triangle;
+
+    const int num_faces = (sizeof (icosphere_triangles)) / (sizeof (struct triangle));
+    for (int i = 0; i < num_faces; i++) {
+
+      struct vertex_normal * an = &icosphere_normals[icosphere_triangles[i].a.normal];
+      io_registers.a.NORMAL = 0
+	| NORMAL__z_component(an->z)
+	| NORMAL__y_component(an->y)
+	| NORMAL__x_component(an->x);
+
+      struct vertex_position * a = &icosphere_positions[icosphere_triangles[i].a.position];
+      io_registers.a.VTX_10 = 0
+	| VTX_10__z_coordinate(a->z)
+	| VTX_10__y_coordinate(a->y)
+	| VTX_10__x_coordinate(a->x);
+
+      struct vertex_position * b = &icosphere_positions[icosphere_triangles[i].b.position];
+      io_registers.a.VTX_10 = 0
+	| VTX_10__z_coordinate(b->z)
+	| VTX_10__y_coordinate(b->y)
+	| VTX_10__x_coordinate(b->x);
+
+      struct vertex_position * c = &icosphere_positions[icosphere_triangles[i].c.position];
+      io_registers.a.VTX_10 = 0
+	| VTX_10__z_coordinate(c->z)
+	| VTX_10__y_coordinate(c->y)
+	| VTX_10__x_coordinate(c->x);
+    }
+
+    // end of the quadrilateral
+    io_registers.a.END_VTXS = 0;
+
+    // wait for the end of the current frame
+    while (io_registers.a.VCOUNT != 262);
+    while (io_registers.a.VCOUNT == 262);
+
+    // wait for the geometry engine
+    while (io_registers.a.GXSTAT & GXSTAT__geometry_engine_busy);
+
+    // swap buffers
+    io_registers.a.SWAP_BUFFERS = 0;
+
+    // increment theta once per frame
+    theta += 1;
+    if (theta >= 360 * 2) {
+      theta = 0;
+    }
+  }
+}

cartridge.lds

@@ -24,7 +24,7 @@ SECTIONS
     KEEP(*(.data.arm9*.bin))
   } AT>rom
 
-  . = 0x02000000 + 0x8000;
+  . = 0x02000000 + 0x390000;
 
   _arm7 = .;
 

models/Makefile

@@ -0,0 +1,4 @@
+all: $(patsubst %.obj,%.h,$(wildcard *.obj))
+
+%.h: %.obj
+	python render_obj_fixed_point_c_source.py $< $(basename $<) > $@

models/cube.h

@@ -30,7 +30,7 @@ struct vertex_normal cube_normals[] = {
   {0, 0, -512},
 };
 
-struct face cube_faces[] = {
+struct quadrilateral cube_quadrilaterals[] = {
   {
     {0, 0, 0},
     {4, 1, 0},

models/model.h

@@ -8,7 +8,13 @@ struct index_ptn {
   uint16_t normal;
 };
 
-struct face {
+struct triangle {
+  struct index_ptn a;
+  struct index_ptn b;
+  struct index_ptn c;
+};
+
+struct quadrilateral {
   struct index_ptn a;
   struct index_ptn b;
   struct index_ptn c;

models/parse_obj_fixed_point.py

@@ -33,7 +33,13 @@ class IndexVTN:
     vertex_normal: int
 
 @dataclass
-class Face:
+class Triangle:
+    a: IndexVTN
+    b: IndexVTN
+    c: IndexVTN
+
+@dataclass
+class Quadrilateral:
     a: IndexVTN
     b: IndexVTN
     c: IndexVTN
@@ -82,8 +88,12 @@ def parse_vertex_indices(args):
 
 def parse_face(args):
     vertices = args.split()
-    assert len(vertices) == 4, vertices
+    if len(vertices) == 3:
-    yield Face(*map(parse_vertex_indices, vertices))
+        yield Triangle(*map(parse_vertex_indices, vertices))
+    elif len(vertices) == 4:
+        yield Quadrilateral(*map(parse_vertex_indices, vertices))
+    else:
+        assert False, (len(vertices), args)
 
 def parse_obj_line(line):
     prefixes = [

models/render_obj_fixed_point_c_source.py

@@ -6,7 +6,8 @@ from parse_obj_fixed_point import parse_obj_file
 from parse_obj_fixed_point import VertexPosition
 from parse_obj_fixed_point import VertexNormal
 from parse_obj_fixed_point import VertexTexture
-from parse_obj_fixed_point import Face
+from parse_obj_fixed_point import Triangle
+from parse_obj_fixed_point import Quadrilateral
 
 vertex_position_fraction_bits = 6 # 4.6
 vertex_normal_fraction_bits = 9 # s.9
@@ -29,12 +30,18 @@ def render_face(face):
         yield from render_index_vtn(index_vtn)
     yield "},"
 
-def render_faces(prefix, faces):
+def render_faces(prefix, name, faces):
-    yield f"struct face {prefix}_faces[] = {{"
+    yield f"struct {name} {prefix}_{name}s[] = {{"
     for face in faces:
         yield from render_face(face)
     yield "};"
 
+def render_triangles(prefix, faces):
+    yield from render_faces(prefix, "triangle", faces)
+
+def render_quadrilateral(prefix, faces):
+    yield from render_faces(prefix, "quadrilateral", faces)
+
 def xyz(vec):
     return (vec.x, vec.y, vec.z)
 
@@ -87,5 +94,8 @@ render(render_header())
 render(render_vertex_positions(prefix, d[VertexPosition]))
 render(render_vertex_texture(prefix, d[VertexTexture]))
 render(render_vertex_normals(prefix, d[VertexNormal]))
-render(render_faces(prefix, d[Face]))
+if Triangle in d:
+    render(render_triangles(prefix, d[Triangle]))
+if Quadrilateral in d:
+    render(render_quadrilateral(prefix, d[Quadrilateral]))
 sys.stdout.write(out.getvalue())

patch.py

@@ -66,8 +66,3 @@ buf[0x15f] = header_crc_b[1]
 
 with open(sys.argv[2], 'wb') as f:
     f.write(buf)
-    assert len(buf) <= 131072, len(buf)
-    i = 131072 - len(buf)
-    while i > 0:
-        f.write(bytes([0]))
-        i -= 1