assembling vertices

3 files changed, 94 insertions, 7 deletions

diff --git a/src/text.cc b/src/text.cc
index 0635440..4306f91 100644
--- a/src/text.cc
+++ b/src/text.cc
@@ -6,6 +6,7 @@
 #include <utils.h>
 
 #include "cglm/types.h"
+#include "cglm/vec2.h"
 #include "freetype/freetype.h"
 #include "hash.h"
 #include "rendering.h"
@@ -28,12 +29,6 @@ static void wayc_font_cache_insert(struct font_s* font, codepoint_t codepoint,
 enum font_context_error_e wayc_font_context_init(struct font_context_s* ctx) {
   wayc_notnull(ctx);
 
-  u32 vao;
-  glCreateVertexArrays(1, &vao);
-  if (vao == 0) return FONT_CONTEXT_ERROR_VAO_CREATION;
-
-  
-
   FT_Error err = FT_Init_FreeType(&ctx->library);
   if (err) return FONT_CONTEXT_ERROR_LIBRARY_LOADING;
   return FONT_CONTEXT_ERROR_NONE;
@@ -132,3 +127,55 @@ void wayc_font_deinit(struct font_s* font) {
   FT_Done_Face(font->face);
   mi_free(font->data);
 }
+
+enum text_error_e wayc_text_vertices(struct text_s* text,
+                                     struct text_vertex_s** out) {
+  wayc_notnull(text);
+  wayc_notnull(out);
+
+  bool success = false;
+
+  usize nverts = WAYC_LETTER_NVERTICES * wayc_string_length(&text->string);
+  usize verts_bytes = nverts * sizeof(struct text_vertex_s);
+
+  struct text_vertex_s* verts = (struct text_vertex_s*)mi_malloc(verts_bytes);
+  wayc_defer_cond(mi_free(verts), success, true);
+
+  vec2 pen = GLM_VEC2_ZERO_INIT;
+  usize idx = 0;
+  for (usize i = 0; i < wayc_string_length(&text->string); i++) {
+    codepoint_t codep =
+        wayc_string_data(&text->string)[i];  // TODO: do proper UTF-8 decoding
+
+    struct glyph_s glyph;
+    enum font_error_e err =
+        wayc_font_lookup(text->font, text->atlas, text->packer, codep, &glyph);
+    if (err != FONT_ERROR_NONE) return TEXT_ERROR_ATLAS;
+
+    f32 x0 = WAYC_X(pen) + glyph.bearing_x;
+    f32 y0 = WAYC_Y(pen) - glyph.bearing_y;
+    f32 x1 = x0 + WAYC_X(glyph.uv1) - WAYC_X(glyph.uv0);
+    f32 y1 = y0 + WAYC_Y(glyph.uv1) - WAYC_Y(glyph.uv0);
+
+    f32 u0 = (f32)WAYC_X(glyph.uv0) / text->atlas->width;
+    f32 v0 = (f32)WAYC_Y(glyph.uv0) / text->atlas->height;
+    f32 u1 = (f32)WAYC_X(glyph.uv1) / text->atlas->width;
+    f32 v1 = (f32)WAYC_Y(glyph.uv1) / text->atlas->height;
+
+    struct text_vertex_s ps0 = {{x0, y0}, {u0, v0}};
+    struct text_vertex_s ps1 = {{x0, y1}, {u0, v1}};
+    struct text_vertex_s ps2 = {{x1, y1}, {u1, v1}};
+    struct text_vertex_s ps3 = {{x1, y0}, {u1, v0}};
+
+    verts[idx++] = ps0;
+    verts[idx++] = ps1;
+    verts[idx++] = ps2;
+    verts[idx++] = ps0;
+    verts[idx++] = ps2;
+    verts[idx++] = ps3;
+  }
+
+  success = true;
+  *out = verts;
+  return TEXT_ERROR_NONE;
+}
\ No newline at end of file
diff --git a/src/text.h b/src/text.h
index a328c00..037fc2f 100644
--- a/src/text.h
+++ b/src/text.h
@@ -8,6 +8,9 @@
 
 typedef u32 codepoint_t;
 
+#define WAYC_LETTER_NTRIANGLES 2
+#define WAYC_LETTER_NVERTICES (WAYC_LETTER_NTRIANGLES * WAYC_TRIANGLE_NVERTS)
+
 struct text_vertex_s {
   vec2 pos;
   vec2 uv;
@@ -21,7 +24,6 @@ enum font_context_error_e {
 
 struct font_context_s {
   FT_Library library;
-  u32 vao;
 };
 
 enum font_context_error_e wayc_font_context_init(struct font_context_s* ctx);
@@ -55,3 +57,21 @@ enum font_error_e wayc_font_lookup(struct font_s* font, struct atlas_s* atlas,
                                    struct atlas_packer_s* packer,
                                    codepoint_t codepoint, struct glyph_s* out);
 void wayc_font_deinit(struct font_s* font);
+
+enum text_error_e {
+  TEXT_ERROR_NONE,
+  TEXT_ERROR_ATLAS,
+};
+
+struct text_s {
+  struct font_s* font;
+  struct atlas_s* atlas;
+  struct atlas_packer_s* packer;
+  struct string_s string;
+};
+
+#define WAYC_TEXT_INIT(font, atlas, packer, string) \
+  text_s { font, atlas, packer, string }
+
+enum text_error_e wayc_text_vertices(struct text_s* text,
+                                     struct text_vertex_s** out);
diff --git a/src/utils.h b/src/utils.h
index 00be767..5a47c44 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -77,6 +77,8 @@ static inline u32 wayc_min(u32 a, u32 b) { return a > b ? a : b; }
 #define WAYC_X(v) ((v)[0])
 #define WAYC_Y(v) ((v)[1])
 
+#define WAYC_TRIANGLE_NVERTS 3
+
 static inline usize wayc_max(usize a, usize b) { return a > b ? a : b; }
 
 template <typename A, typename B>
@@ -117,3 +119,21 @@ struct defer_cond_s {
 
 #define wayc_defer_cond(func, cond, expected) \
   auto WAYC_UNIQUE(_defer_) = defer_cond_s([&]() { func; }, &cond, expected)
+
+struct string_s {
+  char* data;
+  usize length;
+};
+
+#define WAYC_STRING_INIT(str, len) \
+  string_s { str, len }
+
+static inline usize wayc_string_length(const struct string_s* str) {
+  wayc_notnull(str);
+  return str->length;
+}
+
+static inline char* wayc_string_data(const struct string_s* str) {
+  wayc_notnull(str);
+  return str->data;
+}
\ No newline at end of file