medfall

commit 7da76bdccc469437ad702ab20b3fdfc8a64ca8e9
parent c4b7f2676446e8c0434e031c9c6a8ab9557866e1
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Mon Oct 31 22:28:21 +0200

Render the depth buffer

Diffstat:
shadow_map.cc
 | 
87
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 77 insertions(+), 10 deletions(-)
diff --git a/shadow_map.cc b/shadow_map.cc
@@ -11,11 +11,17 @@
 static ImmediateTriangle triangles[ 512000 ];
 static ImmediateContext imm;
 
+static GLuint screen_vao, screen_vbo;
+
 static GLuint prog;
 static GLint at_position;
 static GLint at_colour;
 static GLint un_vp;
 
+static GLuint depth_prog;
+static GLint depth_at_position;
+static GLint depth_un_tex;
+
 static GLuint fbo;
 static GLuint tex_depth;
 
@@ -43,6 +49,32 @@ static const GLchar * frag_src = GLSL(
 	}
 );
 
+static const GLchar * const depth_vert_src = GLSL(
+	in vec2 position;
+
+	out vec2 smooth_position;
+
+	void main() {
+		gl_Position = vec4( position, 0.0, 1.0 );
+		smooth_position = position;
+	}
+);
+
+static const GLchar * depth_frag_src = GLSL(
+	in vec2 smooth_position;
+
+	out vec4 screen_colour;
+
+	uniform sampler2D tex;
+
+	void main() {
+		vec2 texcoord = ( smooth_position + vec2( 1.0, 1.0 ) ) / 2.0;
+		float Depth = texture( tex, texcoord ).x;
+		Depth = 1.0 - (1.0 - Depth) * 25.0;
+		screen_colour = vec4( Depth );
+	}
+);
+
 static void draw_scene( GLint at_position, GLint at_colour ) {
 	immediate_init( &imm, triangles, array_count( triangles ) );
 
@@ -94,7 +126,7 @@ static void update_camera(
 }
 
 static void camera_to_vp( glm::vec3 position, glm::vec3 angles, glm::mat4 * out_vp ) {
-	const glm::mat4 P( glm::perspective( glm::radians( 120.0f ), ( float ) WIDTH / ( float ) HEIGHT, NEAR_PLANE_DEPTH, 100.0f ) );
+	const glm::mat4 P( glm::perspective( glm::radians( 120.0f ), ( float ) WIDTH / ( float ) HEIGHT, NEAR_PLANE_DEPTH, 25.0f ) );
 
 	*out_vp = glm::translate(
 		glm::rotate(
@@ -110,28 +142,53 @@ static void camera_to_vp( glm::vec3 position, glm::vec3 angles, glm::mat4 * out_
 	);
 }
 
+const u32 SHADOW_WIDTH = 1024;
+const u32 SHADOW_HEIGHT = 1024;
+
 extern "C" GAME_INIT( game_init ) {
 	prog = compile_shader( vert_src, frag_src, "screen_colour" );
 	at_position = glGetAttribLocation( prog, "position" );
 	at_colour = glGetAttribLocation( prog, "colour" );
 	un_vp = glGetUniformLocation( prog, "VP" );
 
-	glGenFramebuffers( 1, &fbo );
-	glBindFramebuffer( GL_DRAW_FRAMEBUFFER, fbo );
+	depth_prog = compile_shader( depth_vert_src, depth_frag_src, "screen_colour" );
+	depth_at_position = glGetAttribLocation( depth_prog, "position" );
+	depth_un_tex = glGetUniformLocation( depth_prog, "tex" );
+
 	glGenTextures( 1, &tex_depth );
 	glBindTexture( GL_TEXTURE_2D, tex_depth );
+	glTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL );
+	glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
+	glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
+	glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
+	glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 
-	glTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32F, WIDTH, HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL );
-	glFramebufferTexture2D( GL_DRAW_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, tex_depth, 0 );
+	glGenFramebuffers( 1, &fbo );
+	glBindFramebuffer( GL_FRAMEBUFFER, fbo );
+	glFramebufferTexture2D( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, tex_depth, 0 );
+	glDrawBuffer( GL_NONE );
+	glReadBuffer( GL_NONE );
 
-	glBindFramebuffer( GL_DRAW_FRAMEBUFFER, 0 );
+	assert( glCheckFramebufferStatus( GL_FRAMEBUFFER ) == GL_FRAMEBUFFER_COMPLETE );
+
+	glBindFramebuffer( GL_FRAMEBUFFER, 0 );
 
 	game->pos = glm::vec3( -10, -10, 5 );
 	game->angles = glm::radians( ( glm::vec3( -90, 45, 0 ) ) );
+
+	float verts[] = { -1, -1, -1, 1, 1, -1, 1, 1 };
+	glGenVertexArrays( 1, &screen_vao );
+	glBindVertexArray( screen_vao );
+	glGenBuffers( 1, &screen_vbo );
+	glBindBuffer( GL_ARRAY_BUFFER, screen_vbo );
+	glBufferData( GL_ARRAY_BUFFER, sizeof( verts ), verts, GL_STATIC_DRAW );
+	glEnableVertexAttribArray( depth_at_position );
+	glVertexAttribPointer( depth_at_position, 2, GL_FLOAT, GL_FALSE, sizeof( float ) * 2, 0 );
+	glBindVertexArray( 0 );
+	glBindBuffer( GL_ARRAY_BUFFER, 0 );
 }
 
 extern "C" GAME_FRAME( game_frame ) {
-	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 
 	update_camera( input, dt, game->pos, game->angles, &game->pos, &game->angles );
 	glm::mat4 vp;
@@ -140,13 +197,23 @@ extern "C" GAME_FRAME( game_frame ) {
 	glUseProgram( prog );
 	glUniformMatrix4fv( un_vp, 1, GL_FALSE, glm::value_ptr( vp ) );
 
+	glViewport( 0, 0, SHADOW_WIDTH, SHADOW_HEIGHT );
 	glBindFramebuffer( GL_DRAW_FRAMEBUFFER, fbo );
+	glClear( GL_DEPTH_BUFFER_BIT );
 	draw_scene( at_position, at_colour );
 	glBindFramebuffer( GL_DRAW_FRAMEBUFFER, 0 );
+	glViewport( 0, 0, WIDTH, HEIGHT );
+	glUseProgram( 0 );
+
+	glUseProgram( depth_prog );
+	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+	glActiveTexture( GL_TEXTURE0 );
+	glBindTexture( GL_TEXTURE_2D, tex_depth );
+	glUniform1i( depth_un_tex, 0 );
 
-	glBindFramebuffer( GL_READ_FRAMEBUFFER, fbo );
-	glBlitFramebuffer( 0, 0, WIDTH, HEIGHT, 0, 0, WIDTH, HEIGHT, GL_COLOR_BUFFER_BIT, GL_LINEAR );
-	glBindFramebuffer( GL_READ_FRAMEBUFFER, 0 );
+	glBindVertexArray( screen_vao );
+	glDrawArrays( GL_TRIANGLE_STRIP, 0, 4 );
+	glBindVertexArray( 0 );
 
 	glUseProgram( 0 );
 }