src/vg/vg_lines.h

   1 /* Copyright (C) 2021-2022 Harry Godden (hgn) - All Rights Reserved */
   2
   3 #ifdef VG_3D
   4  typedef v3f line_co;
   5 #else
   6  typedef v2f line_co;
   7 #endif
   8
   9 SHADER_DEFINE( vg_line_shader,
  10 #ifdef VG_3D
  11         "uniform mat4 uPv;"
  12         "layout (location=0) in vec3 a_co;"
  13 #else
  14         "uniform mat3 uPv;"
  15         "layout (location=0) in vec2 a_co;"
  16 #endif
  17         "layout (location=1) in vec4 a_colour;"
  18         ""
  19         "out vec4 s_colour;"
  20         ""
  21         "void main()"
  22         "{"
  23 #ifdef VG_3D
  24         "       vec4 vert_pos = uPv * vec4( a_co, 1.0 );"
  25 #else
  26         "       vec4 vert_pos = vec4( uPv * vec3( a_co, 1.0 ), 1.0 );"
  27 #endif
  28         "  s_colour = a_colour;"
  29         "       gl_Position = vert_pos;"
  30         "}",
  31
  32         // FRAGMENT
  33         "out vec4 FragColor;"
  34         ""
  35         "in vec4 s_colour;"
  36         ""
  37         "void main()"
  38         "{"
  39         "       FragColor = s_colour;"
  40         "}"
  41         ,
  42         UNIFORMS({ "uPv" })
  43 )
  44
  45 struct
  46 {
  47         struct vg_lines_vert
  48         {
  49 #ifdef VG_3D
  50       v3f co;
  51 #else
  52                 v2f co;
  53 #endif
  54
  55                 u32 colour;
  56         }
  57         *buffer;
  58
  59         GLuint vao, vbo;
  60         u32 draw_idx, cap, buffer_size;
  61 }
  62 vg_lines;
  63
  64 static void vg_lines_init(void)
  65 {
  66         SHADER_INIT( vg_line_shader );
  67
  68         glGenVertexArrays( 1, &vg_lines.vao );
  69         glGenBuffers( 1, &vg_lines.vbo );
  70         glBindVertexArray( vg_lines.vao );
  71
  72         glBindBuffer( GL_ARRAY_BUFFER, vg_lines.vbo );
  73
  74         vg_lines.cap = 50000;
  75         vg_lines.buffer_size = vg_lines.cap * sizeof( struct vg_lines_vert );
  76
  77         glBufferData( GL_ARRAY_BUFFER, vg_lines.buffer_size, NULL, GL_DYNAMIC_DRAW );
  78         glBindVertexArray( vg_lines.vao );
  79
  80         glVertexAttribPointer(
  81                 0,
  82                 sizeof( vg_lines.buffer[0].co ) / sizeof(float),
  83                 GL_FLOAT,
  84                 GL_FALSE,
  85                 sizeof( struct vg_lines_vert ),
  86                 (void *)0
  87         );
  88         glEnableVertexAttribArray( 0 );
  89
  90         glVertexAttribPointer(
  91                 1,
  92                 4,
  93                 GL_UNSIGNED_BYTE,
  94                 GL_TRUE,
  95                 sizeof( struct vg_lines_vert ),
  96                 (void*)(offsetof( struct vg_lines_vert, colour ))
  97         );
  98         glEnableVertexAttribArray( 1 );
  99         vg_lines.buffer = malloc( vg_lines.buffer_size );
 100 }
 101
 102 static void vg_lines_free(void)
 103 {
 104         glDeleteVertexArrays( 1, &vg_lines.vao );
 105         glDeleteBuffers( 1, &vg_lines.vbo );
 106
 107         free( vg_lines.buffer );
 108 }
 109
 110 static void vg_lines_drawall( float* projection )
 111 {
 112         SHADER_USE( vg_line_shader );
 113
 114 #ifdef VG_3D
 115    glUniformMatrix4fv
 116 #else
 117         glUniformMatrix3fv
 118 #endif
 119    ( SHADER_UNIFORM( vg_line_shader, "uPv" ), 1, GL_FALSE, projection );
 120
 121         glBindVertexArray( vg_lines.vao );
 122         glBindBuffer( GL_ARRAY_BUFFER, vg_lines.vbo );
 123
 124         glBufferSubData( GL_ARRAY_BUFFER, 0, vg_lines.draw_idx *
 125          sizeof(struct vg_lines_vert), vg_lines.buffer );
 126
 127         glEnable( GL_BLEND );
 128         glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 129         glBlendEquation( GL_FUNC_ADD );
 130
 131         glDrawArrays( GL_LINES, 0, vg_lines.draw_idx );
 132
 133         glDisable( GL_BLEND );
 134         vg_lines.draw_idx = 0;
 135 }
 136
 137 static void vg_line2( line_co from, line_co to, u32 fc, u32 tc )
 138 {
 139         struct vg_lines_vert *v = &vg_lines.buffer[vg_lines.draw_idx];
 140
 141 #ifdef VG_3D
 142         v3_copy( from, v[0].co );
 143         v3_copy( to, v[1].co );
 144 #else
 145         v2_copy( from, v[0].co );
 146         v2_copy( to, v[1].co );
 147 #endif
 148
 149         v[0].colour = fc;
 150         v[1].colour = tc;
 151
 152         vg_lines.draw_idx += 2;
 153 }
 154
 155 static void vg_line( line_co from, line_co to, u32 colour )
 156 {
 157         vg_line2( from, to, colour, colour );
 158 }
 159
 160 static void vg_line_box( line_co min, line_co max, u32 colour )
 161 {
 162 #ifdef VG_3D
 163    /* TODO... */
 164 #else
 165         vg_line( min, (v2f){min[0],max[1]}, colour );
 166         vg_line( (v2f){min[0],max[1]}, max, colour );
 167         vg_line( max, (v2f){max[0],min[1]}, colour );
 168         vg_line( (v2f){max[0],min[1]}, min, colour );
 169 #endif
 170 }