Added canvas example

Added another example to show how to use Nuklear to only draw stuff
to the screen instead of using it for UI (or both).
This commit is contained in:
vurtun 2016-05-27 13:27:29 +02:00
parent 3f7f145819
commit ba1ff9c23c
1 changed files with 455 additions and 0 deletions

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example/canvas.c Normal file
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/* nuklear - v1.00 - public domain */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdarg.h>
#include <string.h>
#include <math.h>
#include <assert.h>
#include <math.h>
#include <time.h>
#include <limits.h>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#define NK_PRIVATE
#define NK_INCLUDE_FIXED_TYPES
#define NK_INCLUDE_STANDARD_IO
#define NK_INCLUDE_DEFAULT_ALLOCATOR
#define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
#define NK_INCLUDE_FONT_BAKING
#define NK_INCLUDE_DEFAULT_FONT
#define NK_IMPLEMENTATION
#include "../nuklear.h"
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
/* macros */
#define WINDOW_WIDTH 1200
#define WINDOW_HEIGHT 800
#define MAX_VERTEX_MEMORY 512 * 1024
#define MAX_ELEMENT_MEMORY 128 * 1024
#define UNUSED(a) (void)a
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAX(a,b) ((a) < (b) ? (b) : (a))
#define LEN(a) (sizeof(a)/sizeof(a)[0])
#define NK_SHADER_VERSION "#version 150\n"
/* ===============================================================
*
* DEVICE
*
* ===============================================================*/
struct device {
struct nk_buffer cmds;
struct nk_draw_null_texture null;
GLuint vbo, vao, ebo;
GLuint prog;
GLuint vert_shdr;
GLuint frag_shdr;
GLint attrib_pos;
GLint attrib_uv;
GLint attrib_col;
GLint uniform_tex;
GLint uniform_proj;
GLuint font_tex;
};
static void
die(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fputs("\n", stderr);
exit(EXIT_FAILURE);
}
static struct nk_image
icon_load(const char *filename)
{
int x,y,n;
GLuint tex;
unsigned char *data = stbi_load(filename, &x, &y, &n, 0);
if (!data) die("[SDL]: failed to load image: %s", filename);
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
stbi_image_free(data);
return nk_image_id((int)tex);
}
static void
device_init(struct device *dev)
{
GLint status;
static const GLchar *vertex_shader =
NK_SHADER_VERSION
"uniform mat4 ProjMtx;\n"
"in vec2 Position;\n"
"in vec2 TexCoord;\n"
"in vec4 Color;\n"
"out vec2 Frag_UV;\n"
"out vec4 Frag_Color;\n"
"void main() {\n"
" Frag_UV = TexCoord;\n"
" Frag_Color = Color;\n"
" gl_Position = ProjMtx * vec4(Position.xy, 0, 1);\n"
"}\n";
static const GLchar *fragment_shader =
NK_SHADER_VERSION
"precision mediump float;\n"
"uniform sampler2D Texture;\n"
"in vec2 Frag_UV;\n"
"in vec4 Frag_Color;\n"
"out vec4 Out_Color;\n"
"void main(){\n"
" Out_Color = Frag_Color * texture(Texture, Frag_UV.st);\n"
"}\n";
nk_buffer_init_default(&dev->cmds);
dev->prog = glCreateProgram();
dev->vert_shdr = glCreateShader(GL_VERTEX_SHADER);
dev->frag_shdr = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(dev->vert_shdr, 1, &vertex_shader, 0);
glShaderSource(dev->frag_shdr, 1, &fragment_shader, 0);
glCompileShader(dev->vert_shdr);
glCompileShader(dev->frag_shdr);
glGetShaderiv(dev->vert_shdr, GL_COMPILE_STATUS, &status);
assert(status == GL_TRUE);
glGetShaderiv(dev->frag_shdr, GL_COMPILE_STATUS, &status);
assert(status == GL_TRUE);
glAttachShader(dev->prog, dev->vert_shdr);
glAttachShader(dev->prog, dev->frag_shdr);
glLinkProgram(dev->prog);
glGetProgramiv(dev->prog, GL_LINK_STATUS, &status);
assert(status == GL_TRUE);
dev->uniform_tex = glGetUniformLocation(dev->prog, "Texture");
dev->uniform_proj = glGetUniformLocation(dev->prog, "ProjMtx");
dev->attrib_pos = glGetAttribLocation(dev->prog, "Position");
dev->attrib_uv = glGetAttribLocation(dev->prog, "TexCoord");
dev->attrib_col = glGetAttribLocation(dev->prog, "Color");
{
/* buffer setup */
GLsizei vs = sizeof(struct nk_draw_vertex);
size_t vp = offsetof(struct nk_draw_vertex, position);
size_t vt = offsetof(struct nk_draw_vertex, uv);
size_t vc = offsetof(struct nk_draw_vertex, col);
glGenBuffers(1, &dev->vbo);
glGenBuffers(1, &dev->ebo);
glGenVertexArrays(1, &dev->vao);
glBindVertexArray(dev->vao);
glBindBuffer(GL_ARRAY_BUFFER, dev->vbo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, dev->ebo);
glEnableVertexAttribArray((GLuint)dev->attrib_pos);
glEnableVertexAttribArray((GLuint)dev->attrib_uv);
glEnableVertexAttribArray((GLuint)dev->attrib_col);
glVertexAttribPointer((GLuint)dev->attrib_pos, 2, GL_FLOAT, GL_FALSE, vs, (void*)vp);
glVertexAttribPointer((GLuint)dev->attrib_uv, 2, GL_FLOAT, GL_FALSE, vs, (void*)vt);
glVertexAttribPointer((GLuint)dev->attrib_col, 4, GL_UNSIGNED_BYTE, GL_TRUE, vs, (void*)vc);
}
glBindTexture(GL_TEXTURE_2D, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
static void
device_upload_atlas(struct device *dev, const void *image, int width, int height)
{
glGenTextures(1, &dev->font_tex);
glBindTexture(GL_TEXTURE_2D, dev->font_tex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)width, (GLsizei)height, 0,
GL_RGBA, GL_UNSIGNED_BYTE, image);
}
static void
device_shutdown(struct device *dev)
{
glDetachShader(dev->prog, dev->vert_shdr);
glDetachShader(dev->prog, dev->frag_shdr);
glDeleteShader(dev->vert_shdr);
glDeleteShader(dev->frag_shdr);
glDeleteProgram(dev->prog);
glDeleteTextures(1, &dev->font_tex);
glDeleteBuffers(1, &dev->vbo);
glDeleteBuffers(1, &dev->ebo);
nk_buffer_free(&dev->cmds);
}
static void
device_draw(struct device *dev, struct nk_context *ctx, int width, int height,
enum nk_anti_aliasing AA)
{
GLfloat ortho[4][4] = {
{2.0f, 0.0f, 0.0f, 0.0f},
{0.0f,-2.0f, 0.0f, 0.0f},
{0.0f, 0.0f,-1.0f, 0.0f},
{-1.0f,1.0f, 0.0f, 1.0f},
};
ortho[0][0] /= (GLfloat)width;
ortho[1][1] /= (GLfloat)height;
/* setup global state */
glEnable(GL_BLEND);
glBlendEquation(GL_FUNC_ADD);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_SCISSOR_TEST);
glActiveTexture(GL_TEXTURE0);
/* setup program */
glUseProgram(dev->prog);
glUniform1i(dev->uniform_tex, 0);
glUniformMatrix4fv(dev->uniform_proj, 1, GL_FALSE, &ortho[0][0]);
{
/* convert from command queue into draw list and draw to screen */
const struct nk_draw_command *cmd;
void *vertices, *elements;
const nk_draw_index *offset = NULL;
/* allocate vertex and element buffer */
glBindVertexArray(dev->vao);
glBindBuffer(GL_ARRAY_BUFFER, dev->vbo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, dev->ebo);
glBufferData(GL_ARRAY_BUFFER, MAX_VERTEX_MEMORY, NULL, GL_STREAM_DRAW);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, MAX_ELEMENT_MEMORY, NULL, GL_STREAM_DRAW);
/* load draw vertices & elements directly into vertex + element buffer */
vertices = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
elements = glMapBuffer(GL_ELEMENT_ARRAY_BUFFER, GL_WRITE_ONLY);
{
/* fill converting configuration */
struct nk_convert_config config;
memset(&config, 0, sizeof(config));
config.global_alpha = 1.0f;
config.shape_AA = AA;
config.line_AA = AA;
config.circle_segment_count = 22;
config.curve_segment_count = 22;
config.arc_segment_count = 22;
config.null = dev->null;
/* setup buffers to load vertices and elements */
{struct nk_buffer vbuf, ebuf;
nk_buffer_init_fixed(&vbuf, vertices, MAX_VERTEX_MEMORY);
nk_buffer_init_fixed(&ebuf, elements, MAX_ELEMENT_MEMORY);
nk_convert(ctx, &dev->cmds, &vbuf, &ebuf, &config);}
}
glUnmapBuffer(GL_ARRAY_BUFFER);
glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);
/* iterate over and execute each draw command */
nk_draw_foreach(cmd, ctx, &dev->cmds)
{
if (!cmd->elem_count) continue;
glBindTexture(GL_TEXTURE_2D, (GLuint)cmd->texture.id);
glScissor(
(GLint)(cmd->clip_rect.x),
(GLint)((height - (GLint)(cmd->clip_rect.y + cmd->clip_rect.h))),
(GLint)(cmd->clip_rect.w),
(GLint)(cmd->clip_rect.h));
glDrawElements(GL_TRIANGLES, (GLsizei)cmd->elem_count, GL_UNSIGNED_SHORT, offset);
offset += cmd->elem_count;
}
nk_clear(ctx);
}
/* default OpenGL state */
glUseProgram(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindVertexArray(0);
glDisable(GL_BLEND);
glDisable(GL_SCISSOR_TEST);
}
/* glfw callbacks (I don't know if there is a easier way to access text and scroll )*/
static void error_callback(int e, const char *d){printf("Error %d: %s\n", e, d);}
static void text_input(GLFWwindow *win, unsigned int codepoint)
{nk_input_unicode((struct nk_context*)glfwGetWindowUserPointer(win), codepoint);}
static void scroll_input(GLFWwindow *win, double _, double yoff)
{UNUSED(_);nk_input_scroll((struct nk_context*)glfwGetWindowUserPointer(win), (float)yoff);}
static void
pump_input(struct nk_context *ctx, GLFWwindow *win)
{
double x, y;
nk_input_begin(ctx);
glfwPollEvents();
nk_input_key(ctx, NK_KEY_DEL, glfwGetKey(win, GLFW_KEY_DELETE) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_ENTER, glfwGetKey(win, GLFW_KEY_ENTER) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_TAB, glfwGetKey(win, GLFW_KEY_TAB) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_BACKSPACE, glfwGetKey(win, GLFW_KEY_BACKSPACE) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_LEFT, glfwGetKey(win, GLFW_KEY_LEFT) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_RIGHT, glfwGetKey(win, GLFW_KEY_RIGHT) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_UP, glfwGetKey(win, GLFW_KEY_UP) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_DOWN, glfwGetKey(win, GLFW_KEY_DOWN) == GLFW_PRESS);
if (glfwGetKey(win, GLFW_KEY_LEFT_CONTROL) == GLFW_PRESS ||
glfwGetKey(win, GLFW_KEY_RIGHT_CONTROL)) {
nk_input_key(ctx, NK_KEY_COPY, glfwGetKey(win, GLFW_KEY_C) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_PASTE, glfwGetKey(win, GLFW_KEY_P) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_CUT, glfwGetKey(win, GLFW_KEY_X) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_CUT, glfwGetKey(win, GLFW_KEY_E) == GLFW_PRESS);
nk_input_key(ctx, NK_KEY_SHIFT, 1);
} else {
nk_input_key(ctx, NK_KEY_COPY, 0);
nk_input_key(ctx, NK_KEY_PASTE, 0);
nk_input_key(ctx, NK_KEY_CUT, 0);
nk_input_key(ctx, NK_KEY_SHIFT, 0);
}
glfwGetCursorPos(win, &x, &y);
nk_input_motion(ctx, (int)x, (int)y);
nk_input_button(ctx, NK_BUTTON_LEFT, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS);
nk_input_button(ctx, NK_BUTTON_MIDDLE, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_MIDDLE) == GLFW_PRESS);
nk_input_button(ctx, NK_BUTTON_RIGHT, (int)x, (int)y, glfwGetMouseButton(win, GLFW_MOUSE_BUTTON_RIGHT) == GLFW_PRESS);
nk_input_end(ctx);
}
static void
canvas_begin(struct nk_context *ctx, int x, int y, int width, int height, struct nk_command_buffer **out)
{
static struct nk_panel layout;
struct nk_rect total_space;
ctx->style.window.spacing = nk_vec2(0,0);
ctx->style.window.padding = nk_vec2(0,0);
nk_begin(ctx, &layout, "Window", nk_rect(x, y, width, height), NK_WINDOW_NO_SCROLLBAR);
nk_window_set_bounds(ctx, nk_rect(x, y, width, height));
total_space = nk_window_get_content_region(ctx);
nk_layout_row_dynamic(ctx, total_space.h, 1);
nk_widget(&total_space, ctx);
*out = nk_window_get_canvas(ctx);
}
static void
canvas_end(struct nk_context *ctx)
{
nk_end(ctx);
ctx->style.window.spacing = nk_vec2(4,4);
ctx->style.window.padding = nk_vec2(8,8);
}
int main(int argc, char *argv[])
{
/* Platform */
static GLFWwindow *win;
int width = 0, height = 0;
/* GUI */
struct device device;
struct nk_font_atlas atlas;
struct nk_context ctx;
/* GLFW */
glfwSetErrorCallback(error_callback);
if (!glfwInit()) {
fprintf(stdout, "[GFLW] failed to init!\n");
exit(1);
}
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
win = glfwCreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "Demo", NULL, NULL);
glfwMakeContextCurrent(win);
glfwSetWindowUserPointer(win, &ctx);
glfwSetCharCallback(win, text_input);
glfwSetScrollCallback(win, scroll_input);
glfwGetWindowSize(win, &width, &height);
/* OpenGL */
glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT);
glewExperimental = 1;
if (glewInit() != GLEW_OK) {
fprintf(stderr, "Failed to setup GLEW\n");
exit(1);
}
/* GUI */
{device_init(&device);
{const void *image; int w, h;
struct nk_font *font;
nk_font_atlas_init_default(&atlas);
nk_font_atlas_begin(&atlas);
font = nk_font_atlas_add_default(&atlas, 13, 0);
image = nk_font_atlas_bake(&atlas, &w, &h, NK_FONT_ATLAS_RGBA32);
device_upload_atlas(&device, image, w, h);
nk_font_atlas_end(&atlas, nk_handle_id((int)device.font_tex), &device.null);
nk_init_default(&ctx, &font->handle);
glEnable(GL_TEXTURE_2D);
while (!glfwWindowShouldClose(win))
{
/* input */
pump_input(&ctx, win);
/* draw */
{struct nk_command_buffer *canvas;
canvas_begin(&ctx, 0, 0, width, height, &canvas);
{
nk_fill_rect(canvas, nk_rect(0,0,width,height), 0, nk_rgb(150,150,150));
nk_fill_rect(canvas, nk_rect(15,15,210,210), 5, nk_rgb(247, 230, 154));
nk_fill_rect(canvas, nk_rect(20,20,200,200), 5, nk_rgb(188, 174, 118));
nk_draw_text(canvas, nk_rect(30, 30, 150, 20), "Text to draw", 12, &font->handle, nk_rgb(188,174,118), nk_rgb(0,0,0));
nk_fill_rect(canvas, nk_rect(250,20,100,100), 0, nk_rgb(0,0,255));
nk_fill_circle(canvas, nk_rect(20,250,100,100), nk_rgb(255,0,0));
nk_fill_triangle(canvas, 250, 250, 350, 250, 300, 350, nk_rgb(0,255,0));
nk_fill_arc(canvas, 300, 180, 50, 0, 3.141592654f * 3.0f / 4.0f, nk_rgb(255,255,0));
{float points[12];
points[0] = 200; points[1] = 250;
points[2] = 250; points[3] = 350;
points[4] = 225; points[5] = 350;
points[6] = 200; points[7] = 300;
points[8] = 175; points[9] = 350;
points[10] = 150; points[11] = 350;
nk_fill_polygon(canvas, points, 6, nk_rgb(255,255,255));}
nk_stroke_line(canvas, 15, 10, 200, 10, 2.0f, nk_rgb(189,45,75));
nk_stroke_rect(canvas, nk_rect(370, 20, 100, 100), 10, 3, nk_rgb(0,0,255));
nk_stroke_curve(canvas, 380, 200, 405, 270, 455, 120, 480, 200, 2, nk_rgb(0,150,220));
nk_stroke_circle(canvas, nk_rect(20, 370, 100, 100), 5, nk_rgb(0,255,120));
nk_stroke_triangle(canvas, 370, 250, 470, 250, 420, 350, 6, nk_rgb(255,0,143));
}
canvas_end(&ctx);}
/* Draw */
glfwGetWindowSize(win, &width, &height);
glViewport(0, 0, width, height);
glClear(GL_COLOR_BUFFER_BIT);
glClearColor(0.2f, 0.2f, 0.2f, 1.0f);
device_draw(&device, &ctx, width, height, NK_ANTI_ALIASING_ON);
glfwSwapBuffers(win);
}}}
nk_font_atlas_clear(&atlas);
nk_free(&ctx);
device_shutdown(&device);
glfwTerminate();
return 0;
}