X-Git-Url: https://harrygodden.com/git/?a=blobdiff_plain;f=vg%2Fvg_lines.h;fp=vg%2Fvg_lines.h;h=b6f52bd385a685358b7ab3e429de9da1e460c058;hb=6836e834f8db725e08015a98401f2be97e5b9849;hp=0000000000000000000000000000000000000000;hpb=b5740880fe3ffe59546bb80173ad3a6e1312648e;p=vg.git

diff --git a/vg/vg_lines.h b/vg/vg_lines.h
new file mode 100644
index 0000000..b6f52bd
--- /dev/null
+++ b/vg/vg_lines.h
@@ -0,0 +1,133 @@
+// Copyright (C) 2021 Harry Godden (hgn) - All Rights Reserved
+
+SHADER_DEFINE( vg_line_shader, 
+
+	// VERTEX
+	"layout (location=0) in vec2 a_co;"
+	"layout (location=1) in vec4 a_colour;"
+	"uniform mat3 uPv;"
+	""
+	"out vec4 s_colour;"
+	""
+	"void main()"
+	"{"
+	"	vec4 vert_pos = vec4( uPv * vec3( a_co, 1.0 ), 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
+	{
+		v2f 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(float* projection)
+{
+	SHADER_USE( vg_line_shader );
+	glUniformMatrix3fv( SHADER_UNIFORM( vg_line_shader, "uPv" ), 1, GL_FALSE, projection );
+	
+	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( v2f from, v2f to, u32 fc, u32 tc )
+{
+	struct vg_lines_vert *v = vg_lines.buffer + vg_lines.draw_idx;
+	v2_copy( from, v[0].co );
+	v2_copy( to, v[1].co );
+	v[0].colour = fc;
+	v[1].colour = tc;
+	
+	vg_lines.draw_idx += 2;
+}
+
+static void vg_line( v2f from, v2f to, u32 colour )
+{
+	vg_line2( from, to, colour, colour );
+}
+
+static void vg_line_box( v2f min, v2f max, u32 colour )
+{
+	vg_line( min, (v2f){min[0],max[1]}, colour );
+	vg_line( (v2f){min[0],max[1]}, max, colour );
+	vg_line( max, (v2f){max[0],min[1]}, colour );
+	vg_line( (v2f){max[0],min[1]}, min, colour );
+}