| 1 | module renderer_mod |
| 2 | use, intrinsic :: iso_c_binding |
| 3 | use gl_bindings |
| 4 | use glyph_mod |
| 5 | use font_mod |
| 6 | use atlas_mod |
| 7 | use shader_mod |
| 8 | implicit none |
| 9 | private |
| 10 | |
| 11 | public :: renderer_t |
| 12 | public :: renderer_create, renderer_destroy |
| 13 | public :: renderer_begin, renderer_draw_char, renderer_draw_string, renderer_flush |
| 14 | public :: renderer_set_projection |
| 15 | |
| 16 | ! Vertex format: position(2) + texcoord(2) + color(4) = 8 floats per vertex |
| 17 | integer, parameter :: FLOATS_PER_VERTEX = 8 |
| 18 | integer, parameter :: VERTICES_PER_QUAD = 6 |
| 19 | integer, parameter :: FLOATS_PER_QUAD = FLOATS_PER_VERTEX * VERTICES_PER_QUAD |
| 20 | integer, parameter :: MAX_QUADS = 4096 |
| 21 | integer, parameter :: MAX_VERTICES = MAX_QUADS * VERTICES_PER_QUAD |
| 22 | integer, parameter :: BUFFER_SIZE = MAX_VERTICES * FLOATS_PER_VERTEX |
| 23 | |
| 24 | type :: renderer_t |
| 25 | integer :: vao = 0 |
| 26 | integer :: vbo = 0 |
| 27 | real(c_float), allocatable :: vertices(:) |
| 28 | integer :: vertex_count = 0 |
| 29 | type(shader_t) :: shader |
| 30 | type(atlas_t) :: atlas |
| 31 | type(font_t) :: font |
| 32 | real(c_float) :: projection(4,4) |
| 33 | logical :: initialized = .false. |
| 34 | end type renderer_t |
| 35 | |
| 36 | ! Embedded shader sources |
| 37 | character(len=*), parameter :: VERT_SHADER = & |
| 38 | "#version 330 core" // c_new_line // & |
| 39 | "layout(location = 0) in vec2 a_position;" // c_new_line // & |
| 40 | "layout(location = 1) in vec2 a_texcoord;" // c_new_line // & |
| 41 | "layout(location = 2) in vec4 a_color;" // c_new_line // & |
| 42 | "uniform mat4 u_projection;" // c_new_line // & |
| 43 | "out vec2 v_texcoord;" // c_new_line // & |
| 44 | "out vec4 v_color;" // c_new_line // & |
| 45 | "void main() {" // c_new_line // & |
| 46 | " gl_Position = u_projection * vec4(a_position, 0.0, 1.0);" // c_new_line // & |
| 47 | " v_texcoord = a_texcoord;" // c_new_line // & |
| 48 | " v_color = a_color;" // c_new_line // & |
| 49 | "}" |
| 50 | |
| 51 | character(len=*), parameter :: FRAG_SHADER = & |
| 52 | "#version 330 core" // c_new_line // & |
| 53 | "in vec2 v_texcoord;" // c_new_line // & |
| 54 | "in vec4 v_color;" // c_new_line // & |
| 55 | "uniform sampler2D u_atlas;" // c_new_line // & |
| 56 | "out vec4 frag_color;" // c_new_line // & |
| 57 | "void main() {" // c_new_line // & |
| 58 | " float alpha = texture(u_atlas, v_texcoord).r;" // c_new_line // & |
| 59 | " frag_color = vec4(v_color.rgb, v_color.a * alpha);" // c_new_line // & |
| 60 | "}" |
| 61 | |
| 62 | contains |
| 63 | |
| 64 | ! Create renderer with font |
| 65 | function renderer_create(font_path, font_size) result(r) |
| 66 | character(len=*), intent(in) :: font_path |
| 67 | integer, intent(in) :: font_size |
| 68 | type(renderer_t) :: r |
| 69 | integer :: vao(1), vbo(1) |
| 70 | integer(c_size_t) :: stride, offset |
| 71 | |
| 72 | ! Load font |
| 73 | r%font = font_load(font_path, font_size) |
| 74 | if (.not. r%font%loaded) then |
| 75 | print *, "Error: Failed to load font" |
| 76 | return |
| 77 | end if |
| 78 | |
| 79 | ! Create atlas from font |
| 80 | r%atlas = atlas_create(r%font) |
| 81 | if (.not. r%atlas%initialized) then |
| 82 | print *, "Error: Failed to create atlas" |
| 83 | call font_destroy(r%font) |
| 84 | return |
| 85 | end if |
| 86 | |
| 87 | ! Create shader |
| 88 | r%shader = shader_create(VERT_SHADER, FRAG_SHADER) |
| 89 | if (.not. r%shader%valid) then |
| 90 | print *, "Error: Failed to create shader" |
| 91 | call atlas_destroy(r%atlas) |
| 92 | call font_destroy(r%font) |
| 93 | return |
| 94 | end if |
| 95 | |
| 96 | ! Create VAO and VBO |
| 97 | call glGenVertexArrays(1, vao) |
| 98 | call glGenBuffers(1, vbo) |
| 99 | r%vao = vao(1) |
| 100 | r%vbo = vbo(1) |
| 101 | |
| 102 | call glBindVertexArray(r%vao) |
| 103 | call glBindBuffer(GL_ARRAY_BUFFER, r%vbo) |
| 104 | |
| 105 | ! Allocate buffer (empty for now) |
| 106 | call glBufferData(GL_ARRAY_BUFFER, & |
| 107 | int(BUFFER_SIZE * c_sizeof(1.0_c_float), c_size_t), & |
| 108 | c_null_ptr, GL_DYNAMIC_DRAW) |
| 109 | |
| 110 | ! Set up vertex attributes |
| 111 | stride = int(FLOATS_PER_VERTEX * c_sizeof(1.0_c_float), c_size_t) |
| 112 | |
| 113 | ! Position: location 0, 2 floats, offset 0 |
| 114 | offset = 0_c_size_t |
| 115 | call glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, int(stride, c_int), offset) |
| 116 | call glEnableVertexAttribArray(0) |
| 117 | |
| 118 | ! Texcoord: location 1, 2 floats, offset 8 bytes |
| 119 | offset = int(2 * c_sizeof(1.0_c_float), c_size_t) |
| 120 | call glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, int(stride, c_int), offset) |
| 121 | call glEnableVertexAttribArray(1) |
| 122 | |
| 123 | ! Color: location 2, 4 floats, offset 16 bytes |
| 124 | offset = int(4 * c_sizeof(1.0_c_float), c_size_t) |
| 125 | call glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, int(stride, c_int), offset) |
| 126 | call glEnableVertexAttribArray(2) |
| 127 | |
| 128 | call glBindVertexArray(0) |
| 129 | |
| 130 | ! Allocate vertex buffer |
| 131 | allocate(r%vertices(BUFFER_SIZE)) |
| 132 | r%vertices = 0.0_c_float |
| 133 | r%vertex_count = 0 |
| 134 | |
| 135 | ! Initialize projection to identity |
| 136 | r%projection = 0.0_c_float |
| 137 | r%projection(1,1) = 1.0_c_float |
| 138 | r%projection(2,2) = 1.0_c_float |
| 139 | r%projection(3,3) = 1.0_c_float |
| 140 | r%projection(4,4) = 1.0_c_float |
| 141 | |
| 142 | r%initialized = .true. |
| 143 | |
| 144 | end function renderer_create |
| 145 | |
| 146 | ! Destroy renderer |
| 147 | subroutine renderer_destroy(r) |
| 148 | type(renderer_t), intent(inout) :: r |
| 149 | integer :: arr(1) |
| 150 | |
| 151 | if (r%vbo > 0) then |
| 152 | arr(1) = r%vbo |
| 153 | call glDeleteBuffers(1, arr) |
| 154 | r%vbo = 0 |
| 155 | end if |
| 156 | |
| 157 | if (r%vao > 0) then |
| 158 | arr(1) = r%vao |
| 159 | call glDeleteVertexArrays(1, arr) |
| 160 | r%vao = 0 |
| 161 | end if |
| 162 | |
| 163 | call shader_destroy(r%shader) |
| 164 | call atlas_destroy(r%atlas) |
| 165 | call font_destroy(r%font) |
| 166 | |
| 167 | if (allocated(r%vertices)) deallocate(r%vertices) |
| 168 | r%initialized = .false. |
| 169 | end subroutine renderer_destroy |
| 170 | |
| 171 | ! Begin a new frame (reset vertex buffer) |
| 172 | subroutine renderer_begin(r) |
| 173 | type(renderer_t), intent(inout) :: r |
| 174 | r%vertex_count = 0 |
| 175 | end subroutine renderer_begin |
| 176 | |
| 177 | ! Set orthographic projection matrix |
| 178 | subroutine renderer_set_projection(r, width, height) |
| 179 | type(renderer_t), intent(inout) :: r |
| 180 | integer, intent(in) :: width, height |
| 181 | |
| 182 | ! Orthographic projection: (0,0) top-left, (width, height) bottom-right |
| 183 | r%projection = 0.0_c_float |
| 184 | r%projection(1,1) = 2.0_c_float / real(width, c_float) |
| 185 | r%projection(2,2) = -2.0_c_float / real(height, c_float) ! Flip Y |
| 186 | r%projection(3,3) = -1.0_c_float |
| 187 | r%projection(4,4) = 1.0_c_float |
| 188 | r%projection(1,4) = -1.0_c_float |
| 189 | r%projection(2,4) = 1.0_c_float |
| 190 | end subroutine renderer_set_projection |
| 191 | |
| 192 | ! Draw a single character at position (x, y) |
| 193 | subroutine renderer_draw_char(r, x, y, codepoint, red, green, blue, alpha) |
| 194 | type(renderer_t), intent(inout) :: r |
| 195 | real, intent(in) :: x, y |
| 196 | integer, intent(in) :: codepoint |
| 197 | real, intent(in) :: red, green, blue, alpha |
| 198 | type(glyph_t) :: g |
| 199 | real(c_float) :: x0, y0, x1, y1 |
| 200 | real(c_float) :: u0, v0, u1, v1 |
| 201 | integer :: base |
| 202 | |
| 203 | if (.not. r%initialized) return |
| 204 | |
| 205 | g = atlas_get_glyph(r%atlas, codepoint) |
| 206 | if (.not. g%valid) return |
| 207 | |
| 208 | ! Check if buffer is full |
| 209 | if (r%vertex_count + VERTICES_PER_QUAD > MAX_VERTICES) then |
| 210 | call renderer_flush(r) |
| 211 | end if |
| 212 | |
| 213 | ! Calculate quad positions |
| 214 | ! x, y is the cursor position (baseline) |
| 215 | x0 = real(x, c_float) + real(g%bearing_x, c_float) |
| 216 | y0 = real(y, c_float) - real(g%bearing_y, c_float) |
| 217 | x1 = x0 + real(g%width, c_float) |
| 218 | y1 = y0 + real(g%height, c_float) |
| 219 | |
| 220 | u0 = g%u0 |
| 221 | v0 = g%v0 |
| 222 | u1 = g%u1 |
| 223 | v1 = g%v1 |
| 224 | |
| 225 | ! Add 6 vertices (2 triangles) for the quad |
| 226 | base = r%vertex_count * FLOATS_PER_VERTEX + 1 |
| 227 | |
| 228 | ! Triangle 1: top-left, bottom-left, bottom-right |
| 229 | ! Vertex 1: top-left |
| 230 | r%vertices(base:base+7) = [x0, y0, u0, v0, & |
| 231 | real(red,c_float), real(green,c_float), & |
| 232 | real(blue,c_float), real(alpha,c_float)] |
| 233 | base = base + 8 |
| 234 | |
| 235 | ! Vertex 2: bottom-left |
| 236 | r%vertices(base:base+7) = [x0, y1, u0, v1, & |
| 237 | real(red,c_float), real(green,c_float), & |
| 238 | real(blue,c_float), real(alpha,c_float)] |
| 239 | base = base + 8 |
| 240 | |
| 241 | ! Vertex 3: bottom-right |
| 242 | r%vertices(base:base+7) = [x1, y1, u1, v1, & |
| 243 | real(red,c_float), real(green,c_float), & |
| 244 | real(blue,c_float), real(alpha,c_float)] |
| 245 | base = base + 8 |
| 246 | |
| 247 | ! Triangle 2: top-left, bottom-right, top-right |
| 248 | ! Vertex 4: top-left |
| 249 | r%vertices(base:base+7) = [x0, y0, u0, v0, & |
| 250 | real(red,c_float), real(green,c_float), & |
| 251 | real(blue,c_float), real(alpha,c_float)] |
| 252 | base = base + 8 |
| 253 | |
| 254 | ! Vertex 5: bottom-right |
| 255 | r%vertices(base:base+7) = [x1, y1, u1, v1, & |
| 256 | real(red,c_float), real(green,c_float), & |
| 257 | real(blue,c_float), real(alpha,c_float)] |
| 258 | base = base + 8 |
| 259 | |
| 260 | ! Vertex 6: top-right |
| 261 | r%vertices(base:base+7) = [x1, y0, u1, v0, & |
| 262 | real(red,c_float), real(green,c_float), & |
| 263 | real(blue,c_float), real(alpha,c_float)] |
| 264 | |
| 265 | r%vertex_count = r%vertex_count + VERTICES_PER_QUAD |
| 266 | |
| 267 | end subroutine renderer_draw_char |
| 268 | |
| 269 | ! Draw a string at position (x, y) |
| 270 | subroutine renderer_draw_string(r, x, y, text, red, green, blue, alpha) |
| 271 | type(renderer_t), intent(inout) :: r |
| 272 | real, intent(in) :: x, y |
| 273 | character(len=*), intent(in) :: text |
| 274 | real, intent(in) :: red, green, blue, alpha |
| 275 | integer :: i, cp |
| 276 | real :: cursor_x |
| 277 | type(glyph_t) :: g |
| 278 | |
| 279 | cursor_x = x |
| 280 | do i = 1, len_trim(text) |
| 281 | cp = ichar(text(i:i)) |
| 282 | call renderer_draw_char(r, cursor_x, y, cp, red, green, blue, alpha) |
| 283 | |
| 284 | ! Advance cursor |
| 285 | g = atlas_get_glyph(r%atlas, cp) |
| 286 | if (g%valid) then |
| 287 | cursor_x = cursor_x + real(g%advance) |
| 288 | end if |
| 289 | end do |
| 290 | end subroutine renderer_draw_string |
| 291 | |
| 292 | ! Flush the vertex buffer to GPU and draw |
| 293 | subroutine renderer_flush(r) |
| 294 | type(renderer_t), intent(inout) :: r |
| 295 | integer(c_size_t) :: data_size |
| 296 | |
| 297 | if (r%vertex_count == 0) return |
| 298 | |
| 299 | ! Enable blending for text |
| 300 | call glEnable(GL_BLEND) |
| 301 | call glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) |
| 302 | |
| 303 | ! Bind shader and set uniforms |
| 304 | call shader_use(r%shader) |
| 305 | call shader_set_projection(r%shader, r%projection) |
| 306 | |
| 307 | ! Bind texture |
| 308 | call glActiveTexture(GL_TEXTURE0) |
| 309 | call glBindTexture(GL_TEXTURE_2D, r%atlas%texture_id) |
| 310 | call glUniform1i(r%shader%atlas_loc, 0) |
| 311 | |
| 312 | ! Upload vertex data |
| 313 | call glBindVertexArray(r%vao) |
| 314 | call glBindBuffer(GL_ARRAY_BUFFER, r%vbo) |
| 315 | |
| 316 | data_size = int(r%vertex_count * FLOATS_PER_VERTEX * c_sizeof(1.0_c_float), c_size_t) |
| 317 | call glBufferSubData_floats(GL_ARRAY_BUFFER, 0_c_size_t, data_size, r%vertices) |
| 318 | |
| 319 | ! Draw |
| 320 | call glDrawArrays(GL_TRIANGLES, 0, r%vertex_count) |
| 321 | |
| 322 | ! Unbind |
| 323 | call glBindVertexArray(0) |
| 324 | call glBindTexture(GL_TEXTURE_2D, 0) |
| 325 | |
| 326 | ! Reset vertex count |
| 327 | r%vertex_count = 0 |
| 328 | |
| 329 | end subroutine renderer_flush |
| 330 | |
| 331 | end module renderer_mod |
| 332 |