adding gfx and ui stuff

gfx/Texture.c

@@ -0,0 +1,137 @@
+#include "Texture.h"
+#include "../os.h"
+#include <math.h>
+
+Texture createTexture(const char* bitmap, int32 width, int32 height) {
+    Texture result = {0};
+    result.width = width;
+    result.height = height;
+    glGenTextures(1, &result.tex_id);
+    glBindTexture(GL_TEXTURE_2D, result.tex_id);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, result.width, result.height, 0, GL_RGB, GL_UNSIGNED_BYTE, bitmap);
+
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);	
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+    glGenerateMipmap(GL_TEXTURE_2D);
+
+    return result;
+}
+
+DefineList(stbtt_bakedchar, STBBakedChar);
+
+static void saveGrayscaleTarga(string location, const char *bytes, int width, int height) {
+    char tgaHeader[18] = {
+        // Image ID length
+        0x00,
+        // Color map type
+        0x00,
+        // Image type
+        0x03,
+        // Color map info (unused)
+        0x0, 0x0, 0x0, 0x0, 0x0,
+        // Image spec
+        0x0, 0x0, // x origin
+        0x0, 0x0, // y origin
+        width & 0xFF, (width >> 8) & 0xFF, // width
+        height & 0xFF, (height >> 8) & 0xFF, // width
+        0x8, // bits per px (depth)
+        0b00000000, // image descriptor
+    };
+    os_writeEntireFile(location, tgaHeader, ArrayCount(tgaHeader));
+    os_fileAppend(location, bytes, width * height);
+}
+
+Font createFont(Arena *arena, string ttfLocation, real32 lineHeight) {
+    const int CODEPOINT_START = 32;
+    const int CODEPOINT_END = 126;
+
+    int32 atlasWidth = ((int32)lineHeight)*(int32)sqrt(CODEPOINT_END - CODEPOINT_START);
+    int32 atlasHeight = ((int32)lineHeight)*(int32)sqrt(CODEPOINT_END - CODEPOINT_START);
+
+    STBBakedCharList bakedCharlist = PushFullListZero(arena, STBBakedCharList, CODEPOINT_END - CODEPOINT_START);
+    string fontFile = os_readEntireFile(arena, ttfLocation);
+
+    stbtt_fontinfo info;
+    stbtt_InitFont(&info, (unsigned char *)fontFile.str, stbtt_GetFontOffsetForIndex((unsigned char *)fontFile.str, 0));
+    int ascent, descent, lineGap;
+    stbtt_GetFontVMetrics(&info, &ascent, &descent, &lineGap);
+    real32 scale = stbtt_ScaleForPixelHeight(&info, lineHeight);
+
+    char *bakedFontBitmap = PushArrayZero(arena, char, atlasWidth*atlasHeight);
+    int32 bake_result = stbtt_BakeFontBitmap(
+            (unsigned char *)fontFile.str, 0,
+            lineHeight,
+            (unsigned char *)bakedFontBitmap, atlasWidth, atlasHeight,
+            CODEPOINT_START, CODEPOINT_END - CODEPOINT_START,
+            bakedCharlist.data);
+
+    GlyphMetaList glyphMeta = PushFullListZero(arena, GlyphMetaList, bakedCharlist.length);
+    real32 x, y;
+    real32 lastX, lastY;
+    for (EachIn(bakedCharlist, i)) {
+        stbtt_aligned_quad q;
+        stbtt_GetBakedQuad(bakedCharlist.data, atlasWidth, atlasHeight, i, &x, &y, &q, 1);
+        glyphMeta.data[i] = (GlyphMeta){
+            .uv0=(Vec2){q.s0, q.t1},
+            .uv1=(Vec2){q.s1, q.t0},
+            .xOffset=q.x0 - lastX,
+            .yOffset=q.y0 + lineHeight + scale * descent,
+            .width=q.x1-q.x0,
+            .height=q.y1-q.y0,
+        };
+        lastX = x;
+        lastY = y;
+    }
+
+    Font result = {0};
+    result.glyphMeta = glyphMeta;
+    result.lineHeight = lineHeight;
+    result.charWidth = bakedCharlist.data[0].xadvance;
+
+    //saveGrayscaleTarga(s("atlas.tga"), bakedFontBitmap, atlasWidth, atlasHeight);
+
+    glGenTextures(1, &result.texId);
+    glBindTexture(GL_TEXTURE_2D, result.texId);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, atlasWidth, atlasHeight, 0, GL_RED, GL_UNSIGNED_BYTE, bakedFontBitmap);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);	
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glGenerateMipmap(GL_TEXTURE_2D);
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    glGenBuffers(1, &result.glyphTableBufId);
+    glBindBuffer(GL_TEXTURE_BUFFER, result.glyphTableBufId);
+    glBufferData(GL_TEXTURE_BUFFER, sizeof(result.glyphMeta.data[0])*result.glyphMeta.length, result.glyphMeta.data, GL_STATIC_DRAW);
+
+    glGenTextures(1, &result.glyphTableTexId);
+    glBindTexture(GL_TEXTURE_BUFFER, result.glyphTableTexId);
+    glTexBuffer(GL_TEXTURE_BUFFER, GL_RGBA32F, result.glyphTableBufId);
+
+    return result;
+}
+
+Texture createTextureFromFile(const char* source_path) {
+    Texture result = {0};
+    glGenTextures(1, &result.tex_id);
+    glBindTexture(GL_TEXTURE_2D, result.tex_id);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);	
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+    int nr_channels;
+    stbi_uc *data = stbi_load(source_path, &result.width, &result.height, &nr_channels, 0);
+    if (data) {
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, result.width, result.height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
+        glGenerateMipmap(GL_TEXTURE_2D);
+    } else {
+        print("Failed to load texture.");
+    }
+    stbi_image_free(data);
+
+    return result;
+}