font rendering

Makefile

@@ -19,7 +19,8 @@ LDFLAGS += $(shell pkg-config --libs glfw3)
 OBJS = \
 	src/gl.o \
 	src/opengl.o \
-	src/test.o
+	src/test.o \
+	src/font.o
 
 all: test.so
 

include/font.h

@@ -0,0 +1,56 @@
+#pragma once
+
+namespace font {
+
+  struct font_desc {
+    char const * const path;
+    int const texture_width;
+    int const texture_height;
+    int const glyph_width;
+    int const glyph_height;
+  };
+
+  font_desc const ter_6x12 = {
+    .path = "font/terminus_128x64_6x12.data",
+    .texture_width = 128,
+    .texture_height = 64,
+    .glyph_width = 6,
+    .glyph_height = 12,
+  };
+  font_desc const ter_8x16 = {
+    .path = "font/terminus_128x128_8x16.data",
+    .texture_width = 128,
+    .texture_height = 128,
+    .glyph_width = 8,
+    .glyph_height = 16,
+  };
+  font_desc const ter_10x18 = {
+    .path = "font/terminus_256x128_10x18.data",
+    .texture_width = 256,
+    .texture_height = 128,
+    .glyph_width = 10,
+    .glyph_height = 18,
+  };
+  font_desc const ter_12x24 = {
+    .path = "font/terminus_256x128_12x24.data",
+    .texture_width = 256,
+    .texture_height = 128,
+    .glyph_width = 12,
+    .glyph_height = 24,
+  };
+
+  struct font {
+    font_desc const * desc;
+    unsigned int texture;
+    int stride;
+    struct {
+      float width;
+      float height;
+    } cell;
+  };
+
+  void load_element_buffer();
+  void load_shader();
+  font load_font(font_desc const& desc);
+  void draw_string(font const& font, char const * const s, int x, int y);
+}

main.lua

@@ -58,6 +58,6 @@ function love.run()
       love.graphics.present()
       love.timer.sleep(0.001)
       local fps = love.timer.getFPS( )
-      print(fps)
+      --print(fps)
    end
 end

minecraft/gen/mc.sh

@@ -1,6 +1,7 @@
 set -eux
 cd ./minecraft/gen
-python mc.py ~/Love2DWorld/region/r.0.0.mcr ../region.0.0 &
+PYTHON=pypy3.11
-python mc.py ~/Love2DWorld/region/r.-1.-1.mcr ../region.-1.-1 &
+$PYTHON mc.py ~/Love2DWorld/region/r.0.0.mcr ../region.0.0 &
-python mc.py ~/Love2DWorld/region/r.0.-1.mcr ../region.0.-1 &
+$PYTHON mc.py ~/Love2DWorld/region/r.-1.-1.mcr ../region.-1.-1 &
-python mc.py ~/Love2DWorld/region/r.-1.0.mcr ../region.-1.0 &
+$PYTHON mc.py ~/Love2DWorld/region/r.0.-1.mcr ../region.0.-1 &
+$PYTHON mc.py ~/Love2DWorld/region/r.-1.0.mcr ../region.-1.0 &

shader/font.frag

@@ -0,0 +1,18 @@
+#version 330 core
+
+uniform sampler2D TextureSampler;
+
+uniform vec2 Cell;
+uniform vec2 Glyph;
+
+out vec4 g_color;
+
+in vec4 PixelTexture;
+
+void main()
+{
+  vec4 sample = texture(TextureSampler, PixelTexture.xy * Cell + Cell * Glyph);
+  float px = sample.x == 0.0 ? 0.0 : 1.0;
+
+  g_color = vec4(vec3(px), 1.0);
+}

shader/font.vert

@@ -0,0 +1,39 @@
+#version 330 core
+
+const vec2 vtx[4] = vec2[](vec2(-1.0,  1.0),  // tl
+                           vec2( 1.0,  1.0),  // tr
+                           vec2( 1.0, -1.0),  // br
+                           vec2(-1.0, -1.0)); // bl
+
+/*
+tl tr
+   br
+
+0 1 2
+tr tl br
+1 0 2
+
+tl
+bl br
+
+2 1 3
+br tl bl
+2 0 3
+
+1 0 2 3
+*/
+
+uniform mat4 Transform;
+
+out vec4 PixelTexture;
+
+void main()
+{
+  vec2 vertex = vtx[gl_VertexID];
+
+  PixelTexture = vec4(vertex * vec2(0.5, -0.5) + 0.5, 0, 0);
+
+  vertex = vertex * vec2(0.5, 0.5) + vec2(0.5, -0.5);
+
+  gl_Position = Transform * vec4(vertex, 0.0, 1.0);
+}

src/font.cpp

@@ -0,0 +1,152 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "directxmath/directxmath.h"
+#include "glad/gl.h"
+#include "opengl.h"
+
+#include "font.h"
+
+namespace font {
+
+  struct location {
+    struct {
+      unsigned int transform;
+      unsigned int texture_sampler;
+      unsigned int cell;
+      unsigned int glyph;
+    } uniform;
+  };
+
+  static location location;
+
+  static unsigned int font_program = -1;
+
+  static unsigned int vertex_array_object = -1;
+  static unsigned int index_buffer = -1;
+
+  void load_element_buffer()
+  {
+    uint8_t const data[] = {
+      1, 0, 2, 3,
+    };
+    int const data_size = (sizeof (data));
+
+    glGenBuffers(1, &index_buffer);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, data_size, data, GL_STATIC_DRAW);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+    glGenVertexArrays(1, &vertex_array_object);
+  }
+
+  void load_shader()
+  {
+    unsigned int program = compile_from_files("shader/font.vert",
+                                              NULL, // geom
+                                              "shader/font.frag");
+
+    location.uniform.transform = glGetUniformLocation(program, "Transform");
+    location.uniform.texture_sampler = glGetUniformLocation(program, "TextureSampler");
+    location.uniform.cell = glGetUniformLocation(program, "Cell");
+    location.uniform.glyph = glGetUniformLocation(program, "Glyph");
+    printf("font uniforms:\n  transform %u\n  texture_sampler %u\n  cell %u\n  glyph %u\n",
+           location.uniform.transform,
+           location.uniform.texture_sampler,
+           location.uniform.cell,
+           location.uniform.glyph
+           );
+
+    font_program = program;
+  }
+
+  font load_font(font_desc const& desc)
+  {
+    unsigned int texture;
+    glGenTextures(1, &texture);
+    glActiveTexture(GL_TEXTURE0);
+    glBindTexture(GL_TEXTURE_2D, texture);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+    int texture_data_size;
+    void * texture_data = read_file(desc.path, &texture_data_size);
+    assert(texture_data != nullptr);
+
+    int width = desc.texture_width;
+    int height = desc.texture_height;
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, texture_data);
+
+    free(texture_data);
+
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    return (font){
+      .desc = &desc,
+      .texture = texture,
+      .stride = desc.texture_width / desc.glyph_width,
+      .cell = { (float)desc.glyph_width / (float)desc.texture_width,
+                (float)desc.glyph_height / (float)desc.texture_height },
+    };
+  }
+
+  inline static XMFLOAT2 glyph_coordinate(font const& font, int ord)
+  {
+    int c = ord - 32;
+    int x = c % font.stride;
+    int y = c / font.stride;
+    XMVECTOR coord = XMVectorSet(x, y, 0, 0);
+    XMFLOAT2 coordf;
+    XMStoreFloat2(&coordf, coord);
+    return coordf;
+  }
+
+  inline static XMFLOAT4X4 glyph_transform(font const& font, int x, int y)
+  {
+    XMMATRIX transform =
+      XMMatrixScaling(font.desc->glyph_width, font.desc->glyph_height, 0)
+      * XMMatrixTranslation(x, -y, 0)
+      * XMMatrixScaling(2.0f / 1024.0f, 2.0f / 1024.0f, 0)
+      * XMMatrixTranslation(-1, 1, 0);
+    XMFLOAT4X4 transformf;
+    XMStoreFloat4x4(&transformf, transform);
+    return transformf;
+  }
+
+  void draw_string(font const& font, char const * const s, int x, int y)
+  {
+    glUseProgram(font_program);
+    glDepthFunc(GL_ALWAYS);
+
+    glActiveTexture(GL_TEXTURE0);
+    glBindTexture(GL_TEXTURE_2D, font.texture);
+
+    glUniform1i(location.uniform.texture_sampler, 0);
+    glUniform2fv(location.uniform.cell, 1, (float *)&font.cell);
+
+    glBindVertexArray(vertex_array_object);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer);
+
+    int i = 0;
+    while (s[i] != 0) {
+      char c = s[i];
+      if (c <= 0x20 || c > 0x7f)
+        continue;
+
+      XMFLOAT4X4 transform = glyph_transform(font, x, y);
+      glUniformMatrix4fv(location.uniform.transform, 1, GL_FALSE, (float *)&transform);
+      XMFLOAT2 glyph = glyph_coordinate(font, c);
+      glUniform2fv(location.uniform.glyph, 1, (float *)&glyph);
+
+      glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_BYTE, (void *)0);
+
+      x += font.desc->glyph_width;
+
+      i += 1;
+    }
+  }
+}

src/test.cpp

@@ -6,6 +6,7 @@
 #include "opengl.h"
 #include "directxmath/directxmath.h"
 #include "test.h"
+#include "font.h"
 
 #include "data.inc"
 
@@ -246,6 +247,8 @@ struct view_state {
 
 view_state view_state;
 
+font::font ter_8x16 = {};
+
 void load()
 {
   fprintf(stderr, "getproc %p\n", SDL_GL_GetProcAddress);
@@ -266,6 +269,14 @@ void load()
   //unsigned int textures_layout = glGetUniformBlockIndex(test_program, "TexturesLayout");
   //glUniformBlockBinding(test_program, textures_layout, 0);
   //printf("textures_layout %d\n", textures_layout);
+
+  //////////////////////////////////////////////////////////////////////
+  // font
+  //////////////////////////////////////////////////////////////////////
+
+  font::load_element_buffer();
+  font::load_shader();
+  ter_8x16 = font::load_font(font::ter_8x16);
 }
 
 void update(float lx, float ly, float rx, float ry, float tl, float tr,
@@ -357,4 +368,6 @@ void draw()
       glDrawElementsInstancedBaseInstance(GL_TRIANGLES, element_count, GL_UNSIGNED_BYTE, indices, instance_count, base_instance);
     }
   }
+
+  font::draw_string(ter_8x16, "test", 10, 10);
 }