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/*
* demoscene-eo, an ASCII art demoscene written as a gift for Emmanuel Otton retirement
* Copyright (C) 2019 XXXXXX XXXXXXX <xxxxxx@xxxxxx.fr>
*
* This file is part of demoscene-eo.
*
* demoscene-eo is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* demoscene-eo is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with demoscene-eo. If not, see <http://www.gnu.org/licenses/>
*/
#include "scene01.h"
// Mostly inspired by CC0 https://gist.github.com/koute/7391344
typedef float t_mat4x4[16];
static inline void mat4x4_ortho( t_mat4x4 out, float left, float right, float bottom, float top, float znear, float zfar )
{
#define T(a, b) (a * 4 + b)
out[T(0,0)] = 2.0f / (right - left);
out[T(0,1)] = 0.0f;
out[T(0,2)] = 0.0f;
out[T(0,3)] = 0.0f;
out[T(1,1)] = 2.0f / (top - bottom);
out[T(1,0)] = 0.0f;
out[T(1,2)] = 0.0f;
out[T(1,3)] = 0.0f;
out[T(2,2)] = -2.0f / (zfar - znear);
out[T(2,0)] = 0.0f;
out[T(2,1)] = 0.0f;
out[T(2,3)] = 0.0f;
out[T(3,0)] = -(right + left) / (right - left);
out[T(3,1)] = -(top + bottom) / (top - bottom);
out[T(3,2)] = -(zfar + znear) / (zfar - znear);
out[T(3,3)] = 1.0f;
#undef T
}
static const char * vertex_shader =
"#version 130\n"
"in vec2 i_position;\n"
"in vec4 i_color;\n"
"out vec4 v_color;\n"
"uniform mat4 u_projection_matrix;\n"
"void main() {\n"
" v_color = i_color;\n"
" gl_Position = u_projection_matrix * vec4( i_position, 0.0, 1.0 );\n"
"}\n";
static const char * fragment_shader =
"#version 130\n"
"in vec4 v_color;\n"
"out vec4 o_color;\n"
"void main() {\n"
" o_color = v_color;\n"
"}\n";
typedef enum t_attrib_id
{
attrib_position,
attrib_color
} t_attrib_id;
int scene01_init_gl(graphical_env_t *ge, scene01_env_t *se) {
GLuint vs, fs, program;
vs = glCreateShader( GL_VERTEX_SHADER );
fs = glCreateShader( GL_FRAGMENT_SHADER );
int length = strlen( vertex_shader );
glShaderSource( vs, 1, ( const GLchar ** )&vertex_shader, &length );
glCompileShader( vs );
GLint status;
glGetShaderiv( vs, GL_COMPILE_STATUS, &status );
if( status == GL_FALSE )
{
fprintf( stderr, "vertex shader compilation failed\n" );
return 1;
}
length = strlen( fragment_shader );
glShaderSource( fs, 1, ( const GLchar ** )&fragment_shader, &length );
glCompileShader( fs );
glGetShaderiv( fs, GL_COMPILE_STATUS, &status );
if( status == GL_FALSE )
{
fprintf( stderr, "fragment shader compilation failed\n" );
return 1;
}
program = glCreateProgram();
glAttachShader( program, vs );
glAttachShader( program, fs );
glBindAttribLocation( program, attrib_position, "i_position" );
glBindAttribLocation( program, attrib_color, "i_color" );
glLinkProgram( program );
glUseProgram( program );
glDisable( GL_DEPTH_TEST );
//glClearColor( 0.5, 0.0, 0.0, 0.0 );
glClearColor( 0.5, 0.5, 0.0, 0.0 );
glViewport( 0, 0, FBUF_W, FBUF_H );
GLuint vbo;
glGenVertexArrays( 1, &(se->vao) );
glGenBuffers( 1, &vbo );
glBindVertexArray( se->vao );
glBindBuffer( GL_ARRAY_BUFFER, vbo );
glEnableVertexAttribArray( attrib_position );
glEnableVertexAttribArray( attrib_color );
glVertexAttribPointer( attrib_color, 4, GL_FLOAT, GL_FALSE, sizeof( float ) * 6, 0 );
glVertexAttribPointer( attrib_position, 2, GL_FLOAT, GL_FALSE, sizeof( float ) * 6, ( void * )(4 * sizeof(float)) );
const GLfloat g_vertex_buffer_data[] = {
/* R, G, B, A, X, Y */
1, 0, 0, 1, 0, 0,
0, 1, 0, 1, FBUF_W, 0,
0, 0, 1, 1, FBUF_W, FBUF_H,
1, 0, 0, 1, 0, 0,
0, 0, 1, 1, FBUF_W, FBUF_H,
1, 1, 1, 1, 0, FBUF_H
};
glBufferData( GL_ARRAY_BUFFER, sizeof( g_vertex_buffer_data ), g_vertex_buffer_data, GL_STATIC_DRAW );
t_mat4x4 projection_matrix;
mat4x4_ortho( projection_matrix, 0.0f, (float)FBUF_W, (float)FBUF_H, 0.0f, 0.0f, 100.0f );
glUniformMatrix4fv( glGetUniformLocation( program, "u_projection_matrix" ), 1, GL_FALSE, projection_matrix );
return 0;
}
int scene01_init_sdl(graphical_env_t *ge, scene01_env_t *se) {
return 0;
}
int scene01_init_caca(graphical_env_t *ge, scene01_env_t *se) {
return 0;
}
void scene01_free_gl(graphical_env_t *ge, scene01_env_t *se) {
//TODO
}
void scene01_free_sdl(graphical_env_t *ge, scene01_env_t *se) {
}
void scene01_free_caca(graphical_env_t *ge, scene01_env_t *se) {
}
int scene01_next_gl(graphical_env_t *ge, scene01_env_t *se) {
SDL_Renderer *r = ge->gl_rndr;
// https://gist.github.com/Twinklebear/8265888
// https://forums.libsdl.org/viewtopic.php?p=51634
glClear(GL_COLOR_BUFFER_BIT);
glBindVertexArray(se->vao);
glDrawArrays(GL_TRIANGLES, 0, 6);
// [...]
SDL_GL_SwapWindow(ge->gl_win);
// Download the rendered texture from videocard to main memory
SDL_RenderReadPixels(r, NULL, 0, ge->raw_target, FBUF_W*4);
return 0;
}
int scene01_next_sdl(graphical_env_t *ge, scene01_env_t *se) {
return 0;
}
int scene01_next_caca(graphical_env_t *ge, scene01_env_t *se) {
// Shorthands
caca_canvas_t *cv = ge->cv;
int w = ge->w, h = ge->h;
Uint32 frame = ge->sc_framecount;
// "convert" the raw pixel stream from SDL to ASCII art on caca canevas
caca_set_dither_gamma(ge->d, 1.0);
caca_dither_bitmap(cv, 0, 0, w, h, ge->d, ge->raw_target);
// Add things on top of caca canvas
caca_set_color_ansi(cv, CACA_WHITE, CACA_BLACK);
caca_put_str(cv, (w-17)/2, h/2, "This is a message");
if ( frame >= 300 ) {
return 1;
}
return 0;
}
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