billboards!

src/rendering/twn_quads.c

@@ -1,30 +1,171 @@
 #include "twn_draw_c.h"
 
+#include <stb_ds.h>
+
 #include <stddef.h>
 
 
-struct QuadBatch collect_quad_batch(const Primitive2D primitives[], size_t len) {
-    if (primitives[0].type == PRIMITIVE_2D_SPRITE)
-        return collect_sprite_batch(primitives, len);
-    else if (primitives[0].type == PRIMITIVE_2D_RECT)
-        return collect_rect_batch(primitives, len);
-    else
-        SDL_assert(false);
-
-    return (struct QuadBatch){0};
-}
-
-
-/* assumes that orthogonal matrix setup is done already */
-void render_quad_batch(const Primitive2D primitives[],
-                       const struct QuadBatch batch)
+void finally_render_quads(const Primitive2D primitives[],
+                          const struct QuadBatch batch,
+                          const VertexBuffer buffer)
 {
-    if (primitives[0].type == PRIMITIVE_2D_SPRITE)
-        render_sprite_batch(primitives, batch);
-    else if (primitives[0].type == PRIMITIVE_2D_RECT)
-        render_rect_batch(primitives, batch);
-    else
-        SDL_assert(false);
+    DeferredCommandDraw command = {0};
 
-    return (struct QuadBatch){0};
+    GLsizei off = 0, voff = 0, uvoff = 0, coff = 0;
+
+    if (!batch.constant_colored && batch.textured) {
+        off   = offsetof(ElementIndexedQuad, v1);
+        voff  = offsetof(ElementIndexedQuad, v0);
+        uvoff = offsetof(ElementIndexedQuad, uv0);
+        coff  = offsetof(ElementIndexedQuad, c0);
+    } else if (batch.constant_colored && batch.textured) {
+        off   = offsetof(ElementIndexedQuadWithoutColor, v1);
+        voff  = offsetof(ElementIndexedQuadWithoutColor, v0);
+        uvoff = offsetof(ElementIndexedQuadWithoutColor, uv0);
+    } else if (!batch.constant_colored && !batch.textured) {
+        off   = offsetof(ElementIndexedQuadWithoutTexture, v1);
+        voff  = offsetof(ElementIndexedQuadWithoutTexture, v0);
+        coff  = offsetof(ElementIndexedQuad, c0);
+    } else if (batch.constant_colored && !batch.textured) {
+        off   = offsetof(ElementIndexedQuadWithoutColorWithoutTexture, v1);
+        voff  = offsetof(ElementIndexedQuadWithoutColorWithoutTexture, v0);
+    }
+
+    command.vertices = (AttributeArrayPointer) {
+        .arity = 2,
+        .type = GL_FLOAT,
+        .stride = off,
+        .offset = voff,
+        .buffer = buffer
+    };
+
+    if (batch.textured)
+        command.texcoords = (AttributeArrayPointer) {
+            .arity = 2,
+            .type = GL_FLOAT,
+            .stride = off,
+            .offset = uvoff,
+            .buffer = buffer
+        };
+
+    if (!batch.constant_colored) {
+        command.colors = (AttributeArrayPointer) {
+            .arity = 4,
+            .type = GL_UNSIGNED_BYTE,
+            .stride = off,
+            .offset = coff,
+            .buffer = buffer
+        };
+    } else {
+        command.constant_colored = true;
+        command.color = primitives[0].sprite.color;
+    }
+
+    if (batch.textured) {
+        command.textured = true;
+        command.texture_key = batch.texture_key;
+        command.texture_repeat = batch.repeat;
+    }
+
+    command.element_buffer = get_quad_element_buffer();
+    command.element_count = 6 * (GLsizei)batch.size;
+    command.range_end = 6 * (GLsizei)batch.size;
+
+    use_texture_mode(batch.mode);
+
+    DeferredCommand final_command = {
+        .type = DEFERRED_COMMAND_TYPE_DRAW,
+        .draw = command
+    };
+
+    arrpush(deferred_commands, final_command);
+}
+
+
+size_t get_quad_payload_size(struct QuadBatch batch) {
+    if (batch.constant_colored && batch.textured)
+        return sizeof (ElementIndexedQuadWithoutColor);
+    else if (!batch.constant_colored && batch.textured)
+        return sizeof (ElementIndexedQuad);
+    else if (batch.constant_colored && !batch.textured)
+        return sizeof (ElementIndexedQuadWithoutColorWithoutTexture);
+    else if (!batch.constant_colored && !batch.textured)
+        return sizeof (ElementIndexedQuadWithoutTexture);
+
+    SDL_assert(false);
+    return 0;
+}
+
+
+bool push_quad_payload_to_vertex_buffer_builder(struct QuadBatch batch,
+                                                VertexBufferBuilder *builder,
+                                                Vec2 v0, Vec2 v1, Vec2 v2, Vec2 v3,
+                                                Vec2 uv0, Vec2 uv1, Vec2 uv2, Vec2 uv3,
+                                                Color color)
+{
+    if (!batch.constant_colored && batch.textured) {
+        ElementIndexedQuad const buffer_element = {
+            .v0 = v0,
+            .v1 = v1,
+            .v2 = v2,
+            .v3 = v3,
+
+            .uv0 = uv0,
+            .uv1 = uv1,
+            .uv2 = uv2,
+            .uv3 = uv3,
+
+            /* equal for all (flat shaded) */
+            .c0 = color,
+            // .c1 = color,
+            .c2 = color,
+            // .c3 = color,
+        };
+
+        return push_to_vertex_buffer_builder(builder, &buffer_element, sizeof buffer_element);
+
+    } else if (batch.constant_colored && batch.textured) {
+        ElementIndexedQuadWithoutColor const buffer_element = {
+            .v0 = v0,
+            .v1 = v1,
+            .v2 = v2,
+            .v3 = v3,
+
+            .uv0 = uv0,
+            .uv1 = uv1,
+            .uv2 = uv2,
+            .uv3 = uv3,
+        };
+
+        return push_to_vertex_buffer_builder(builder, &buffer_element, sizeof buffer_element);
+
+    } else if (!batch.constant_colored && !batch.textured) {
+        ElementIndexedQuadWithoutTexture const buffer_element = {
+            .v0 = v0,
+            .v1 = v1,
+            .v2 = v2,
+            .v3 = v3,
+
+            /* equal for all (flat shaded) */
+            .c0 = color,
+            // .c1 = color,
+            .c2 = color,
+            // .c3 = color,
+        };
+
+        return push_to_vertex_buffer_builder(builder, &buffer_element, sizeof buffer_element);
+
+    } else if (batch.constant_colored && !batch.textured) {
+        ElementIndexedQuadWithoutColorWithoutTexture const buffer_element = {
+            .v0 = v0,
+            .v1 = v1,
+            .v2 = v2,
+            .v3 = v3,
+        };
+
+        return push_to_vertex_buffer_builder(builder, &buffer_element, sizeof buffer_element);
+    }
+
+    SDL_assert(false);
+    return false;
 }