gastro: render test scene

1 files changed, 203 insertions, 0 deletions

diff --git a/gastro/src/test.c b/gastro/src/test.c
new file mode 100644
index 0000000..46ce6b1
--- /dev/null
+++ b/gastro/src/test.c
@@ -0,0 +1,203 @@
+#include <lcq/gastro/test.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+static i64 off = 0;
+static gastro_program program;
+static qoi_color *texture;
+static i64 texture_width;
+static i64 texture_height;
+
+#define QUADIDX(p0, p1, p2, p3) p0, p1, p2, p2, p3, p0
+#define COLOR(r, g, b) gastro_fix_new(r), gastro_fix_new(g), gastro_fix_new(b)
+static void draw_quad(gastro_ctx *ctx, gastro_program *p) {
+    gastro_fix sz = GASTRO_FIX_HALF;
+    gastro_fix verts[] = {
+        /* front */
+        -sz, -sz, -sz, 0, 0,
+        +sz, -sz, -sz, GASTRO_FIX_ONE, 0,
+        +sz, +sz, -sz, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        -sz, +sz, -sz, 0, GASTRO_FIX_ONE
+    };
+    i64 idxs[] = {
+        QUADIDX(0, 1, 2, 3), /* front */
+    };
+    gastro_render_triangles(ctx, p, verts, 5, idxs, 2);
+}
+static void draw_cube(gastro_ctx *ctx, gastro_program *p) {
+    static gastro_fix verts[] = {
+        /* front */
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, 0, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, 0, GASTRO_FIX_ONE,
+        /* right */
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, 0, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, 0, GASTRO_FIX_ONE,
+        /* left */
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, 0, 0,
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, 0, GASTRO_FIX_ONE,
+        /* top */
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, 0, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, 0, GASTRO_FIX_ONE,
+        /* bottom */
+        -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, 0, 0,
+        +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, 0, GASTRO_FIX_ONE,
+        /* back */
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, 0, 0,
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, +GASTRO_FIX_HALF, 0, GASTRO_FIX_ONE
+    };
+    static i64 idxs[] = {
+        QUADIDX(0, 1, 2, 3), /* front */
+        QUADIDX(4, 5, 6, 7), /* right */
+        QUADIDX(8, 9, 10, 11), /* left */
+        QUADIDX(12, 13, 14, 15), /* top */
+        QUADIDX(16, 17, 18, 19), /* bottom */
+        QUADIDX(20, 21, 22, 23) /* back */
+    };
+    gastro_render_triangles(ctx, p, verts, 5, idxs, 12);
+}
+static void draw_pyramid(gastro_ctx *ctx, gastro_program *p) {
+    static gastro_fix verts[] = {
+        /* front */
+        0, +GASTRO_FIX_HALF, 0, 0, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        /* right */
+        0, +GASTRO_FIX_HALF, 0, 0, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        /* left */
+        0, +GASTRO_FIX_HALF, 0, 0, 0,
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        /* back */
+        0, +GASTRO_FIX_HALF, 0, 0, 0,
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        /* bottom */
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, 0, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, GASTRO_FIX_ONE, 0,
+        +GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, GASTRO_FIX_ONE, GASTRO_FIX_ONE,
+        -GASTRO_FIX_HALF, -GASTRO_FIX_HALF, +GASTRO_FIX_HALF, 0, GASTRO_FIX_ONE,
+    };
+    static i64 idxs[] = {
+        0, 1, 2,
+        3, 4, 5,
+        6, 7, 8,
+        9, 10, 11,
+        QUADIDX(12, 13, 14, 15),
+    };
+    gastro_render_triangles(ctx, p, verts, 5, idxs, 6);
+}
+
+static gastro_vec4 vertex_shader(gastro_ctx *ctx, gastro_vec3 in, gastro_fix *attrs, i64 attrs_len) {
+    gastro_fix x = gastro_fix_from_double((double) off / 1000.0);
+    gastro_vec4 v = gastro_vec4_new(in.x, in.y, in.z, GASTRO_FIX_ONE);
+    gastro_mat4x4 scale = gastro_mat4x4_new(
+        gastro_fix_from_double(1.0), 0, 0, 0,
+        0, gastro_fix_from_double(1.0), 0, 0,
+        0, 0, gastro_fix_from_double(1.0), 0,
+        0, 0, 0, GASTRO_FIX_ONE
+    );
+    u8 theta = (u8) (off / 4);
+    /* u8 theta = 13; */
+    gastro_mat4x4 rot = gastro_mat4x4_new(
+        GASTRO_FIX_ONE, 0, 0, 0,
+        0, gastro_cos(theta), -gastro_sin(theta), 0,
+        0, gastro_sin(theta), gastro_cos(theta), 0,
+        0, 0, 0, GASTRO_FIX_ONE
+    );
+    gastro_mat4x4 trans = gastro_mat4x4_new(
+        GASTRO_FIX_ONE, 0, 0, gastro_fix_new(0), /* x,*/
+        0, GASTRO_FIX_ONE, 0, gastro_fix_new(1),
+        0, 0, GASTRO_FIX_ONE, gastro_fix_new(-3),
+        0, 0, 0, GASTRO_FIX_ONE
+    );
+    gastro_mat4x4 proj = gastro_mat4x4_new(
+        GASTRO_FIX_ONE, 0, 0, 0,
+        0, GASTRO_FIX_ONE, 0, 0,
+        0, 0, GASTRO_FIX_ONE, 0,
+        0, 0, GASTRO_FIX_ONE, 0
+    );
+    v = gastro_mat4x4_mul_vec4(scale, v);
+    v = gastro_mat4x4_mul_vec4(rot, v);
+    v = gastro_mat4x4_mul_vec4(trans, v);
+    v = gastro_mat4x4_mul_vec4(proj, v);
+    return v;
+}
+
+static gastro_color fragment_shader_texture(gastro_ctx *ctx, gastro_vec3 in, gastro_fix *attrs, i64 attrs_len) {
+    gastro_fix u = attrs[0];
+    gastro_fix v = attrs[1];
+    i64 x = gastro_fix_to_i64(gastro_fix_mul(gastro_fix_new(texture_width), u));
+    i64 y = gastro_fix_to_i64(gastro_fix_mul(gastro_fix_new(texture_height), v));
+    qoi_color c = texture[y * texture_width + x];
+    return gastro_color_new(c.r, c.g, c.b, c.a);
+}
+
+static gastro_color fragment_shader_teapot(gastro_ctx *ctx, gastro_vec3 in, gastro_fix *attrs, i64 attrs_len) {
+    u8 col = (u8) gastro_fix_to_i64(
+        gastro_fix_mul(
+            gastro_fix_new(0xff),
+            gastro_fix_div(in.z, gastro_fix_new(8))
+        )
+    );
+    return gastro_color_new(0xff - col, 0xff - col, 0xff - col, 0xff);
+}
+
+static void load_image(char *path) {
+    FILE *f;
+    u8 *buf;
+    i64 len;
+    qoi_decoder q;
+    qoi_header h;
+    qoi_color *pixels;
+    if (!(f = fopen(path, "r"))) {
+        fprintf(stderr, "failed to open file: %s\n", path);
+        return;
+    }
+    fseek(f, 0, SEEK_END);
+    len = ftell(f);
+    fseek(f, 0, SEEK_SET);
+    buf = calloc((size_t) len, sizeof(u8));
+    fread(buf, sizeof(u8), (size_t) len, f);
+    qoi_decoder_new(&q, buf, len);
+    if (!qoi_decode_header(&q, &h)) {
+        fprintf(stderr, "failed to decode header\n");
+        return;
+    }
+    pixels = calloc(h.width * h.height, sizeof(qoi_color));
+    qoi_decode(&q, &h, pixels);
+    texture = pixels;
+    texture_width = h.width;
+    texture_height = h.height;
+}
+
+bool gastro_test_create() {
+    program.vertex = vertex_shader;
+    program.fragment = fragment_shader_texture;
+    load_image("test.qoi");
+}
+
+void gastro_test_render(gastro_ctx *ctx) {
+    gastro_draw_clear(ctx, gastro_color_new(0, 0, 0, 0xff));
+    for (i64 i = 0; i < 1; ++i) {
+        draw_pyramid(ctx, &program);
+    }
+    /* draw_quad(&ctx, &p); */
+    /* draw_model(&ctx, &p); */
+    off += 1;
+    off %= 256 * 64;
+}