engine: debug lines module

[fishladder.git] / vg / vg_lines.h

diff --git a/vg/vg_lines.h b/vg/vg_lines.h
new file mode 100644 (file)
index 0000000..81b0091
--- /dev/null
+++ b/vg/vg_lines.h
@@ -0,0 +1,126 @@
+// Copyright (C) 2021 Harry Godden (hgn) - All Rights Reserved
+
+SHADER_DEFINE( vg_line_shader, 
+
+       // VERTEX
+       "layout (location=0) in vec3 a_co;"
+       "layout (location=1) in vec4 a_colour;"
+       "uniform mat4 uPv;"
+       ""
+       "out vec4 s_colour;"
+       ""
+       "void main()"
+       "{"
+       "       vec4 vert_pos = uPv * vec4( a_co, 1.0 );"
+       "  s_colour = a_colour;"
+       "       gl_Position = vert_pos;"
+       "}",
+       
+       // FRAGMENT
+       "out vec4 FragColor;"
+       ""
+       "in vec4 s_colour;"
+       ""
+       "void main()"
+       "{"
+       "       FragColor = s_colour;"
+       "}"
+       ,
+       UNIFORMS({ "uPv" })
+)
+
+struct
+{
+       struct vg_lines_vert
+       {
+               vec3 co;
+               u32 colour;
+       }
+       *buffer;
+       
+       GLuint vao, vbo;
+       u32 draw_idx, cap, buffer_size;
+       
+}
+vg_lines;
+
+static void vg_lines_init(void)
+{
+       SHADER_INIT( vg_line_shader );
+       
+       glGenVertexArrays( 1, &vg_lines.vao );
+       glGenBuffers( 1, &vg_lines.vbo );
+       glBindVertexArray( vg_lines.vao );
+       
+       glBindBuffer( GL_ARRAY_BUFFER, vg_lines.vbo );
+       
+       vg_lines.cap = 10000;
+       vg_lines.buffer_size = vg_lines.cap * sizeof( struct vg_lines_vert );
+       
+       glBufferData( GL_ARRAY_BUFFER, vg_lines.buffer_size, NULL, GL_DYNAMIC_DRAW );
+       glBindVertexArray( vg_lines.vao );
+       
+       glVertexAttribPointer( 
+               0, 
+               sizeof( vg_lines.buffer[0].co ) / sizeof(float), 
+               GL_FLOAT, 
+               GL_FALSE, 
+               sizeof( struct vg_lines_vert ), 
+               (void *)0 
+       );
+       glEnableVertexAttribArray( 0 );
+       
+       glVertexAttribPointer( 
+               1, 
+               4, 
+               GL_UNSIGNED_BYTE, 
+               GL_TRUE, 
+               sizeof( struct vg_lines_vert ), 
+               (void*)(offsetof( struct vg_lines_vert, colour ))
+       );
+       glEnableVertexAttribArray( 1 );
+       vg_lines.buffer = malloc( vg_lines.buffer_size );
+}
+
+static void vg_lines_free(void)
+{
+       glDeleteVertexArrays( 1, &vg_lines.vao );
+       glDeleteBuffers( 1, &vg_lines.vbo );
+       
+       free( vg_lines.buffer );
+}
+
+static void vg_lines_drawall(void)
+{
+       SHADER_USE( vg_line_shader );
+       glUniformMatrix4fv( SHADER_UNIFORM( vg_line_shader, "uPv" ), 1, GL_FALSE, (float *)vg_pv );
+       
+       glBindVertexArray( vg_lines.vao );
+       glBindBuffer( GL_ARRAY_BUFFER, vg_lines.vbo );
+       
+       glBufferSubData( GL_ARRAY_BUFFER, 0, vg_lines.draw_idx * sizeof(struct vg_lines_vert), vg_lines.buffer );
+       glEnable( GL_BLEND );
+       glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
+       glBlendEquation( GL_FUNC_ADD );
+       
+       glDrawArrays( GL_LINES, 0, vg_lines.draw_idx );
+       
+       glDisable( GL_BLEND );
+       vg_lines.draw_idx = 0;
+}
+
+static void vg_line2( vec3 from, vec3 to, u32 fc, u32 tc )
+{
+       struct vg_lines_vert *v = vg_lines.buffer + vg_lines.draw_idx;
+       glm_vec3_copy( from, v[0].co );
+       glm_vec3_copy( to, v[1].co );
+       v[0].colour = fc;
+       v[1].colour = tc;
+       
+       vg_lines.draw_idx += 2;
+}
+
+static void vg_line( vec3 from, vec3 to, u32 colour )
+{
+       vg_line2( from, to, colour, colour );
+}