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#include "graphics.h"
#include "shader.h"
void GLAPIENTRY
MessageCallback(GLenum source,
GLenum type,
GLuint id,
GLenum severity,
GLsizei length,
const GLchar* message,
const void* userParam) {
fprintf( stderr, "GL CALLBACK: %s type = 0x%x, severity = 0x%x, message = %s\n",
( type == GL_DEBUG_TYPE_ERROR ? "** GL ERROR **" : "" ),
type, severity, message );
}
const char* vertexShader = "#version 330 core\n\
layout (location = 0) in vec2 pos;\n\
layout (location = 1) in vec2 uv;\n\
\n\
uniform vec2 u_screen_size;\n\
uniform vec2 u_offset;\n\
\n\
out vec2 o_uv;\n\
\n\
void main() {\n\
o_uv = uv;\n\
gl_Position = vec4((((2.0 * (pos + u_offset)) / u_screen_size) - vec2(1.0)), 0.0, 1.0);\n\
}";
const char* fragmentShader = "#version 330 core\n\
uniform sampler2D u_texture;\n\
in vec2 o_uv;\n\
\n\
layout (location = 0) out vec4 frag_color;\n\
\n\
void main() {\n\
float d = texture(u_texture, o_uv).r;\n\
float aaf = fwidth(d);\n\
float alpha = smoothstep(0.5 - aaf, 0.5 + aaf, d);\n\
frag_color = vec4(1.0, 1.0, 1.0, alpha);\n\
}";
bool init_gl(client_state* state) {
EGLint attrs[] = {
EGL_RENDERABLE_TYPE, EGL_OPENGL_BIT,
EGL_CONFORMANT, EGL_OPENGL_BIT,
EGL_RED_SIZE, 8,
EGL_GREEN_SIZE, 8,
EGL_BLUE_SIZE, 8,
EGL_ALPHA_SIZE, 8,
EGL_DEPTH_SIZE, 24,
EGL_NONE
};
state->egl_window = wl_egl_window_create(state->surface, state->width, state->height);
if (!state->egl_window) {
fprintf(stderr, "ewindow\n");
return false;
}
state->egl_display = eglGetDisplay(state->display);
if (state->egl_display == EGL_NO_DISPLAY) {
fprintf(stderr, "edisplay\n");
return false;
}
{
EGLint major, minor;
if (eglInitialize(state->egl_display, &major, &minor) != EGL_TRUE) {
fprintf(stderr, "eglinit\n");
return false;
}
printf("EGL version %u.%u\n", major, minor);
}
eglBindAPI(EGL_OPENGL_API);
EGLint num_configs;
if (eglChooseConfig(state->egl_display, attrs, &state->egl_config, 1, &num_configs) != EGL_TRUE) {
fprintf(stderr, "econfig: %d\n", eglGetError());
return false;
}
state->egl_surface = eglCreateWindowSurface(state->egl_display, state->egl_config,
(EGLNativeWindowType)state->egl_window, NULL);
if (state->egl_surface == EGL_NO_SURFACE) {
fprintf(stderr, "esurface\n");
return false;
}
state->egl_context = eglCreateContext(state->egl_display, state->egl_config,
EGL_NO_CONTEXT, NULL);
if (state->egl_context == EGL_NO_CONTEXT) {
fprintf(stderr, "econtext: %x\n", eglGetError());
return false;
}
eglMakeCurrent(state->egl_display, state->egl_surface, state->egl_surface, state->egl_context);
if (!gladLoadGL()) {
fprintf(stderr, "gladLoadGL");
return false;
}
{
GLint major, minor;
glGetIntegerv(GL_MAJOR_VERSION, &major);
glGetIntegerv(GL_MINOR_VERSION, &minor);
printf("GL version %u.%u\n", major, minor);
}
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_DEBUG_OUTPUT);
glDebugMessageCallback(MessageCallback, 0);
state->text_shader = createShader(vertexShader, fragmentShader);
state->screen_size_uniform = glGetUniformLocation(state->text_shader, "u_screen_size");
state->offset_uniform = glGetUniformLocation(state->text_shader, "u_offset");
return true;
}
void render_frame(client_state *state) {
glViewport(0, 0, state->width, state->height);
glClearColor(0.0, 0.0, 0.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBindVertexArray(state->input_buffer_text.vao);
glBindBuffer(GL_ARRAY_BUFFER, state->input_buffer_text.vbo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, state->input_buffer_text.ebo);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, state->atlas.texture);
glUseProgram(state->text_shader);
glUniform2f(state->screen_size_uniform, state->width, state->height);
glUniform2f(state->offset_uniform, 0.0f, 0.0f);
glDrawElements(GL_TRIANGLES, state->input_buffer_text.num_elements, GL_UNSIGNED_INT, 0);
eglSwapBuffers(state->egl_display, state->egl_surface);
}
typedef struct {
float x, y, u, v;
} vert_t;
void initTextBuffer(client_state* state, text_buffer_t* buffer, char* text, size_t text_len) {
// generate openg bullshit
glGenVertexArrays(1, &buffer->vao);
glBindVertexArray(buffer->vao);
glGenBuffers(1, &buffer->vbo);
glGenBuffers(1, &buffer->ebo);
// TODO for unicode - check for missing characters, iterate over "unicode characters" not chars
// TODO for all fonts - possibly kerning
// generate vertices
vert_t vertices[text_len * 4];
uint32_t indices[text_len * 6];
buffer->num_elements = text_len * 6;
float pen_x = 0;
for (int n = 0; n < text_len; n++) {
char c = text[n];
metric_t* m = &state->atlas.metrics[(int)c];
float start_x = pen_x + m->bearing_x;
float start_y = m->bearing_y;
uint32_t base_vert = n * 4;
uint32_t base_idx = n * 6;
// bottom left vert
vert_t v = { .x=start_x, .y=start_y, .u=m->texture_x_start, .v=0.0f};
vertices[base_vert + 0] = v;
// top left vert
v.y -= m->bitmap_height;
v.v = ((float)m->bitmap_height / state->atlas.height);
vertices[base_vert + 1] = v;
// top right vert
v.x += m->bitmap_width;
v.u = m->texture_x_end;
vertices[base_vert + 2] = v;
// bottom right vert
v.y = start_y;
v.v = 0.0f;
vertices[base_vert + 3] = v;
// indices
indices[base_idx + 0] = base_vert + 0;
indices[base_idx + 1] = base_vert + 1;
indices[base_idx + 2] = base_vert + 2;
indices[base_idx + 3] = base_vert + 0;
indices[base_idx + 4] = base_vert + 2;
indices[base_idx + 5] = base_vert + 3;
// go forward
pen_x += m->advance_x;
}
for (int i = 0, n = 0; i < sizeof(vertices) / sizeof(vert_t); ++i, !(i % 4) ? n++ : false) {
vert_t v = vertices[i];
printf("%c: (%f, %f, %f, %f)\n", text[n], v.x, v.y, v.u, v.v);
}
// vertex buffer
glBindBuffer(GL_ARRAY_BUFFER, buffer->vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
// index buffer
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer->ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
// vertex attributes
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(vert_t), (void*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(vert_t), (void*)(2 * sizeof(float)));
glEnableVertexAttribArray(1);
}
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