1 /*
2  * Nuklear - 1.32.0 - public domain
3  * no warrenty implied; use at your own risk.
4  * authored from 2015-2016 by Micha Mettke
5  */
6 /*
7  * ==============================================================
8  *
9  *                              API
10  *
11  * ===============================================================
12  */
13 #ifndef NK_SDL_GL3_H_
14 #define NK_SDL_GL3_H_
15 
16 #include <SDL2/SDL.h>
17 #include <SDL2/SDL_opengl.h>
18 
19 NK_API struct nk_context*   nk_sdl_init(SDL_Window *win);
20 NK_API void                 nk_sdl_font_stash_begin(struct nk_font_atlas **atlas);
21 NK_API void                 nk_sdl_font_stash_end(void);
22 NK_API int                  nk_sdl_handle_event(SDL_Event *evt);
23 NK_API void                 nk_sdl_render(enum nk_anti_aliasing , int max_vertex_buffer, int max_element_buffer);
24 NK_API void                 nk_sdl_shutdown(void);
25 NK_API void                 nk_sdl_device_destroy(void);
26 NK_API void                 nk_sdl_device_create(void);
27 
28 #endif
29 
30 /*
31  * ==============================================================
32  *
33  *                          IMPLEMENTATION
34  *
35  * ===============================================================
36  */
37 #ifdef NK_SDL_GL3_IMPLEMENTATION
38 
39 #include <string.h>
40 
41 struct nk_sdl_device {
42     struct nk_buffer cmds;
43     struct nk_draw_null_texture null;
44     GLuint vbo, vao, ebo;
45     GLuint prog;
46     GLuint vert_shdr;
47     GLuint frag_shdr;
48     GLint attrib_pos;
49     GLint attrib_uv;
50     GLint attrib_col;
51     GLint uniform_tex;
52     GLint uniform_proj;
53     GLuint font_tex;
54 };
55 
56 struct nk_sdl_vertex {
57     float position[2];
58     float uv[2];
59     nk_byte col[4];
60 };
61 
62 static struct nk_sdl {
63     SDL_Window *win;
64     struct nk_sdl_device ogl;
65     struct nk_context ctx;
66     struct nk_font_atlas atlas;
67 } sdl;
68 
69 #ifdef __APPLE__
70   #define NK_SHADER_VERSION "#version 150\n"
71 #else
72   #define NK_SHADER_VERSION "#version 300 es\n"
73 #endif
74 NK_API void
nk_sdl_device_create(void)75 nk_sdl_device_create(void)
76 {
77     GLint status;
78     static const GLchar *vertex_shader =
79         NK_SHADER_VERSION
80         "uniform mat4 ProjMtx;\n"
81         "in vec2 Position;\n"
82         "in vec2 TexCoord;\n"
83         "in vec4 Color;\n"
84         "out vec2 Frag_UV;\n"
85         "out vec4 Frag_Color;\n"
86         "void main() {\n"
87         "   Frag_UV = TexCoord;\n"
88         "   Frag_Color = Color;\n"
89         "   gl_Position = ProjMtx * vec4(Position.xy, 0, 1);\n"
90         "}\n";
91     static const GLchar *fragment_shader =
92         NK_SHADER_VERSION
93         "precision mediump float;\n"
94         "uniform sampler2D Texture;\n"
95         "in vec2 Frag_UV;\n"
96         "in vec4 Frag_Color;\n"
97         "out vec4 Out_Color;\n"
98         "void main(){\n"
99         "   Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
100         "}\n";
101 
102     struct nk_sdl_device *dev = &sdl.ogl;
103     nk_buffer_init_default(&dev->cmds);
104     dev->prog = glCreateProgram();
105     dev->vert_shdr = glCreateShader(GL_VERTEX_SHADER);
106     dev->frag_shdr = glCreateShader(GL_FRAGMENT_SHADER);
107     glShaderSource(dev->vert_shdr, 1, &vertex_shader, 0);
108     glShaderSource(dev->frag_shdr, 1, &fragment_shader, 0);
109     glCompileShader(dev->vert_shdr);
110     glCompileShader(dev->frag_shdr);
111     glGetShaderiv(dev->vert_shdr, GL_COMPILE_STATUS, &status);
112     assert(status == GL_TRUE);
113     glGetShaderiv(dev->frag_shdr, GL_COMPILE_STATUS, &status);
114     assert(status == GL_TRUE);
115     glAttachShader(dev->prog, dev->vert_shdr);
116     glAttachShader(dev->prog, dev->frag_shdr);
117     glLinkProgram(dev->prog);
118     glGetProgramiv(dev->prog, GL_LINK_STATUS, &status);
119     assert(status == GL_TRUE);
120 
121     dev->uniform_tex = glGetUniformLocation(dev->prog, "Texture");
122     dev->uniform_proj = glGetUniformLocation(dev->prog, "ProjMtx");
123     dev->attrib_pos = glGetAttribLocation(dev->prog, "Position");
124     dev->attrib_uv = glGetAttribLocation(dev->prog, "TexCoord");
125     dev->attrib_col = glGetAttribLocation(dev->prog, "Color");
126 
127     {
128         /* buffer setup */
129         GLsizei vs = sizeof(struct nk_sdl_vertex);
130         size_t vp = offsetof(struct nk_sdl_vertex, position);
131         size_t vt = offsetof(struct nk_sdl_vertex, uv);
132         size_t vc = offsetof(struct nk_sdl_vertex, col);
133 
134         glGenBuffers(1, &dev->vbo);
135         glGenBuffers(1, &dev->ebo);
136         glGenVertexArrays(1, &dev->vao);
137 
138         glBindVertexArray(dev->vao);
139         glBindBuffer(GL_ARRAY_BUFFER, dev->vbo);
140         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, dev->ebo);
141 
142         glEnableVertexAttribArray((GLuint)dev->attrib_pos);
143         glEnableVertexAttribArray((GLuint)dev->attrib_uv);
144         glEnableVertexAttribArray((GLuint)dev->attrib_col);
145 
146         glVertexAttribPointer((GLuint)dev->attrib_pos, 2, GL_FLOAT, GL_FALSE, vs, (void*)vp);
147         glVertexAttribPointer((GLuint)dev->attrib_uv, 2, GL_FLOAT, GL_FALSE, vs, (void*)vt);
148         glVertexAttribPointer((GLuint)dev->attrib_col, 4, GL_UNSIGNED_BYTE, GL_TRUE, vs, (void*)vc);
149     }
150 
151     glBindTexture(GL_TEXTURE_2D, 0);
152     glBindBuffer(GL_ARRAY_BUFFER, 0);
153     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
154     glBindVertexArray(0);
155 }
156 
157 NK_INTERN void
nk_sdl_device_upload_atlas(const void * image,int width,int height)158 nk_sdl_device_upload_atlas(const void *image, int width, int height)
159 {
160     struct nk_sdl_device *dev = &sdl.ogl;
161     glGenTextures(1, &dev->font_tex);
162     glBindTexture(GL_TEXTURE_2D, dev->font_tex);
163     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
164     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
165     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)width, (GLsizei)height, 0,
166                 GL_RGBA, GL_UNSIGNED_BYTE, image);
167 }
168 
169 NK_API void
nk_sdl_device_destroy(void)170 nk_sdl_device_destroy(void)
171 {
172     struct nk_sdl_device *dev = &sdl.ogl;
173     glDetachShader(dev->prog, dev->vert_shdr);
174     glDetachShader(dev->prog, dev->frag_shdr);
175     glDeleteShader(dev->vert_shdr);
176     glDeleteShader(dev->frag_shdr);
177     glDeleteProgram(dev->prog);
178     glDeleteTextures(1, &dev->font_tex);
179     glDeleteBuffers(1, &dev->vbo);
180     glDeleteBuffers(1, &dev->ebo);
181     nk_buffer_free(&dev->cmds);
182 }
183 
184 NK_API void
nk_sdl_render(enum nk_anti_aliasing AA,int max_vertex_buffer,int max_element_buffer)185 nk_sdl_render(enum nk_anti_aliasing AA, int max_vertex_buffer, int max_element_buffer)
186 {
187     struct nk_sdl_device *dev = &sdl.ogl;
188     int width, height;
189     int display_width, display_height;
190     struct nk_vec2 scale;
191     GLfloat ortho[4][4] = {
192         {2.0f, 0.0f, 0.0f, 0.0f},
193         {0.0f,-2.0f, 0.0f, 0.0f},
194         {0.0f, 0.0f,-1.0f, 0.0f},
195         {-1.0f,1.0f, 0.0f, 1.0f},
196     };
197     SDL_GetWindowSize(sdl.win, &width, &height);
198     SDL_GL_GetDrawableSize(sdl.win, &display_width, &display_height);
199     ortho[0][0] /= (GLfloat)width;
200     ortho[1][1] /= (GLfloat)height;
201 
202     scale.x = (float)display_width/(float)width;
203     scale.y = (float)display_height/(float)height;
204 
205     /* setup global state */
206     glViewport(0,0,display_width,display_height);
207     glEnable(GL_BLEND);
208     glBlendEquation(GL_FUNC_ADD);
209     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
210     glDisable(GL_CULL_FACE);
211     glDisable(GL_DEPTH_TEST);
212     glEnable(GL_SCISSOR_TEST);
213     glActiveTexture(GL_TEXTURE0);
214 
215     /* setup program */
216     glUseProgram(dev->prog);
217     glUniform1i(dev->uniform_tex, 0);
218     glUniformMatrix4fv(dev->uniform_proj, 1, GL_FALSE, &ortho[0][0]);
219     {
220         /* convert from command queue into draw list and draw to screen */
221         const struct nk_draw_command *cmd;
222         void *vertices, *elements;
223         const nk_draw_index *offset = NULL;
224         struct nk_buffer vbuf, ebuf;
225 
226         /* allocate vertex and element buffer */
227         glBindVertexArray(dev->vao);
228         glBindBuffer(GL_ARRAY_BUFFER, dev->vbo);
229         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, dev->ebo);
230 
231         glBufferData(GL_ARRAY_BUFFER, max_vertex_buffer, NULL, GL_STREAM_DRAW);
232         glBufferData(GL_ELEMENT_ARRAY_BUFFER, max_element_buffer, NULL, GL_STREAM_DRAW);
233 
234         /* load vertices/elements directly into vertex/element buffer */
235         vertices = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
236         elements = glMapBuffer(GL_ELEMENT_ARRAY_BUFFER, GL_WRITE_ONLY);
237         {
238             /* fill convert configuration */
239             struct nk_convert_config config;
240             static const struct nk_draw_vertex_layout_element vertex_layout[] = {
241                 {NK_VERTEX_POSITION, NK_FORMAT_FLOAT, NK_OFFSETOF(struct nk_sdl_vertex, position)},
242                 {NK_VERTEX_TEXCOORD, NK_FORMAT_FLOAT, NK_OFFSETOF(struct nk_sdl_vertex, uv)},
243                 {NK_VERTEX_COLOR, NK_FORMAT_R8G8B8A8, NK_OFFSETOF(struct nk_sdl_vertex, col)},
244                 {NK_VERTEX_LAYOUT_END}
245             };
246             NK_MEMSET(&config, 0, sizeof(config));
247             config.vertex_layout = vertex_layout;
248             config.vertex_size = sizeof(struct nk_sdl_vertex);
249             config.vertex_alignment = NK_ALIGNOF(struct nk_sdl_vertex);
250             config.null = dev->null;
251             config.circle_segment_count = 22;
252             config.curve_segment_count = 22;
253             config.arc_segment_count = 22;
254             config.global_alpha = 1.0f;
255             config.shape_AA = AA;
256             config.line_AA = AA;
257 
258             /* setup buffers to load vertices and elements */
259             nk_buffer_init_fixed(&vbuf, vertices, (nk_size)max_vertex_buffer);
260             nk_buffer_init_fixed(&ebuf, elements, (nk_size)max_element_buffer);
261             nk_convert(&sdl.ctx, &dev->cmds, &vbuf, &ebuf, &config);
262         }
263         glUnmapBuffer(GL_ARRAY_BUFFER);
264         glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);
265 
266         /* iterate over and execute each draw command */
267         nk_draw_foreach(cmd, &sdl.ctx, &dev->cmds) {
268             if (!cmd->elem_count) continue;
269             glBindTexture(GL_TEXTURE_2D, (GLuint)cmd->texture.id);
270             glScissor((GLint)(cmd->clip_rect.x * scale.x),
271                 (GLint)((height - (GLint)(cmd->clip_rect.y + cmd->clip_rect.h)) * scale.y),
272                 (GLint)(cmd->clip_rect.w * scale.x),
273                 (GLint)(cmd->clip_rect.h * scale.y));
274             glDrawElements(GL_TRIANGLES, (GLsizei)cmd->elem_count, GL_UNSIGNED_SHORT, offset);
275             offset += cmd->elem_count;
276         }
277         nk_clear(&sdl.ctx);
278     }
279 
280     glUseProgram(0);
281     glBindBuffer(GL_ARRAY_BUFFER, 0);
282     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
283     glBindVertexArray(0);
284     glDisable(GL_BLEND);
285     glDisable(GL_SCISSOR_TEST);
286 }
287 
288 static void
nk_sdl_clipbard_paste(nk_handle usr,struct nk_text_edit * edit)289 nk_sdl_clipbard_paste(nk_handle usr, struct nk_text_edit *edit)
290 {
291     const char *text = SDL_GetClipboardText();
292     if (text) nk_textedit_paste(edit, text, nk_strlen(text));
293     (void)usr;
294 }
295 
296 static void
nk_sdl_clipbard_copy(nk_handle usr,const char * text,int len)297 nk_sdl_clipbard_copy(nk_handle usr, const char *text, int len)
298 {
299     char *str = 0;
300     (void)usr;
301     if (!len) return;
302     str = (char*)malloc((size_t)len+1);
303     if (!str) return;
304     memcpy(str, text, (size_t)len);
305     str[len] = '\0';
306     SDL_SetClipboardText(str);
307     free(str);
308 }
309 
310 NK_API struct nk_context*
nk_sdl_init(SDL_Window * win)311 nk_sdl_init(SDL_Window *win)
312 {
313     sdl.win = win;
314     nk_init_default(&sdl.ctx, 0);
315     sdl.ctx.clip.copy = nk_sdl_clipbard_copy;
316     sdl.ctx.clip.paste = nk_sdl_clipbard_paste;
317     sdl.ctx.clip.userdata = nk_handle_ptr(0);
318     nk_sdl_device_create();
319     return &sdl.ctx;
320 }
321 
322 NK_API void
nk_sdl_font_stash_begin(struct nk_font_atlas ** atlas)323 nk_sdl_font_stash_begin(struct nk_font_atlas **atlas)
324 {
325     nk_font_atlas_init_default(&sdl.atlas);
326     nk_font_atlas_begin(&sdl.atlas);
327     *atlas = &sdl.atlas;
328 }
329 
330 NK_API void
nk_sdl_font_stash_end(void)331 nk_sdl_font_stash_end(void)
332 {
333     const void *image; int w, h;
334     image = nk_font_atlas_bake(&sdl.atlas, &w, &h, NK_FONT_ATLAS_RGBA32);
335     nk_sdl_device_upload_atlas(image, w, h);
336     nk_font_atlas_end(&sdl.atlas, nk_handle_id((int)sdl.ogl.font_tex), &sdl.ogl.null);
337     if (sdl.atlas.default_font)
338         nk_style_set_font(&sdl.ctx, &sdl.atlas.default_font->handle);
339 
340 }
341 
342 NK_API int
nk_sdl_handle_event(SDL_Event * evt)343 nk_sdl_handle_event(SDL_Event *evt)
344 {
345     struct nk_context *ctx = &sdl.ctx;
346     if (evt->type == SDL_KEYUP || evt->type == SDL_KEYDOWN) {
347         /* key events */
348         int down = evt->type == SDL_KEYDOWN;
349         const Uint8* state = SDL_GetKeyboardState(0);
350         SDL_Keycode sym = evt->key.keysym.sym;
351         if (sym == SDLK_RSHIFT || sym == SDLK_LSHIFT)
352             nk_input_key(ctx, NK_KEY_SHIFT, down);
353         else if (sym == SDLK_DELETE)
354             nk_input_key(ctx, NK_KEY_DEL, down);
355         else if (sym == SDLK_RETURN)
356             nk_input_key(ctx, NK_KEY_ENTER, down);
357         else if (sym == SDLK_TAB)
358             nk_input_key(ctx, NK_KEY_TAB, down);
359         else if (sym == SDLK_BACKSPACE)
360             nk_input_key(ctx, NK_KEY_BACKSPACE, down);
361         else if (sym == SDLK_HOME) {
362             nk_input_key(ctx, NK_KEY_TEXT_START, down);
363             nk_input_key(ctx, NK_KEY_SCROLL_START, down);
364         } else if (sym == SDLK_END) {
365             nk_input_key(ctx, NK_KEY_TEXT_END, down);
366             nk_input_key(ctx, NK_KEY_SCROLL_END, down);
367         } else if (sym == SDLK_PAGEDOWN) {
368             nk_input_key(ctx, NK_KEY_SCROLL_DOWN, down);
369         } else if (sym == SDLK_PAGEUP) {
370             nk_input_key(ctx, NK_KEY_SCROLL_UP, down);
371         } else if (sym == SDLK_z)
372             nk_input_key(ctx, NK_KEY_TEXT_UNDO, down && state[SDL_SCANCODE_LCTRL]);
373         else if (sym == SDLK_r)
374             nk_input_key(ctx, NK_KEY_TEXT_REDO, down && state[SDL_SCANCODE_LCTRL]);
375         else if (sym == SDLK_c)
376             nk_input_key(ctx, NK_KEY_COPY, down && state[SDL_SCANCODE_LCTRL]);
377         else if (sym == SDLK_v)
378             nk_input_key(ctx, NK_KEY_PASTE, down && state[SDL_SCANCODE_LCTRL]);
379         else if (sym == SDLK_x)
380             nk_input_key(ctx, NK_KEY_CUT, down && state[SDL_SCANCODE_LCTRL]);
381         else if (sym == SDLK_b)
382             nk_input_key(ctx, NK_KEY_TEXT_LINE_START, down && state[SDL_SCANCODE_LCTRL]);
383         else if (sym == SDLK_e)
384             nk_input_key(ctx, NK_KEY_TEXT_LINE_END, down && state[SDL_SCANCODE_LCTRL]);
385         else if (sym == SDLK_UP)
386             nk_input_key(ctx, NK_KEY_UP, down);
387         else if (sym == SDLK_DOWN)
388             nk_input_key(ctx, NK_KEY_DOWN, down);
389         else if (sym == SDLK_LEFT) {
390             if (state[SDL_SCANCODE_LCTRL])
391                 nk_input_key(ctx, NK_KEY_TEXT_WORD_LEFT, down);
392             else nk_input_key(ctx, NK_KEY_LEFT, down);
393         } else if (sym == SDLK_RIGHT) {
394             if (state[SDL_SCANCODE_LCTRL])
395                 nk_input_key(ctx, NK_KEY_TEXT_WORD_RIGHT, down);
396             else nk_input_key(ctx, NK_KEY_RIGHT, down);
397         } else return 0;
398         return 1;
399     } else if (evt->type == SDL_MOUSEBUTTONDOWN || evt->type == SDL_MOUSEBUTTONUP) {
400         /* mouse button */
401         int down = evt->type == SDL_MOUSEBUTTONDOWN;
402         const int x = evt->button.x, y = evt->button.y;
403         if (evt->button.button == SDL_BUTTON_LEFT) {
404             if (evt->button.clicks > 1)
405                 nk_input_button(ctx, NK_BUTTON_DOUBLE, x, y, down);
406             nk_input_button(ctx, NK_BUTTON_LEFT, x, y, down);
407         } else if (evt->button.button == SDL_BUTTON_MIDDLE)
408             nk_input_button(ctx, NK_BUTTON_MIDDLE, x, y, down);
409         else if (evt->button.button == SDL_BUTTON_RIGHT)
410             nk_input_button(ctx, NK_BUTTON_RIGHT, x, y, down);
411         return 1;
412     } else if (evt->type == SDL_MOUSEMOTION) {
413         /* mouse motion */
414         if (ctx->input.mouse.grabbed) {
415             int x = (int)ctx->input.mouse.prev.x, y = (int)ctx->input.mouse.prev.y;
416             nk_input_motion(ctx, x + evt->motion.xrel, y + evt->motion.yrel);
417         } else nk_input_motion(ctx, evt->motion.x, evt->motion.y);
418         return 1;
419     } else if (evt->type == SDL_TEXTINPUT) {
420         /* text input */
421         nk_glyph glyph;
422         memcpy(glyph, evt->text.text, NK_UTF_SIZE);
423         nk_input_glyph(ctx, glyph);
424         return 1;
425     } else if (evt->type == SDL_MOUSEWHEEL) {
426         /* mouse wheel */
427         nk_input_scroll(ctx,nk_vec2((float)evt->wheel.x,(float)evt->wheel.y));
428         return 1;
429     }
430     return 0;
431 }
432 
433 NK_API
nk_sdl_shutdown(void)434 void nk_sdl_shutdown(void)
435 {
436     nk_font_atlas_clear(&sdl.atlas);
437     nk_free(&sdl.ctx);
438     nk_sdl_device_destroy();
439     memset(&sdl, 0, sizeof(sdl));
440 }
441 
442 #endif
443