Merge pull request #1 from computersarecool/dev

Dev

Author: computersarecool

README.md

@@ -2,8 +2,23 @@
 *Examples of DSA OpenGL*
 
 ## Description
-These are a collection of examples of modern OpenGL using Direct Sate Access (DSA).
-They are mostly API examples but some have interesting graphical output.
+The evolution of OpenGL basically goes like this:
+Immediate mode -> Modern OpenGL (3.0+) -> [Direct State Access](https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_direct_state_access.txt) -> Vulkan.
+
+Direct State Access in OpenGL provides a nice balance between verbosity and control. In particular, getting rid of the “state-machine” construct makes programming feel more similar to C++.
+
+Early OpenGL does not provide enough control to the user, but Vulkan can make getting started with graphics very intimidating and prototyping / experimenting with the GPU challenging.
+
+
+The examples contained in this repo examine many, but not all, of the DSA OpenGL techniques, and use almost, but not but not quite, exclusively, use DSA. There is still a lot more to cover.
+
+A very small amount of redundant code was abstracted in the `base_app` class. This takes care of loading shaders and setting up a window.
+
+Most of the examples in this project are API examples with limited graphical output, but there is some interesting graphical output.
+
+<p align="center">
+  <img src="https://i.imgur.com/PRn5OeT.png" title="Raytracer example" />
+</p>
 
 ### Dependencies
 - [GLM](https://github.com/g-truc/glm) (math)
@@ -41,11 +56,23 @@ These provided basic needed functionality.
 ## Functionality
 
 #### base_app
-This is an abstract base class and should be ignored
+This is an abstract base class used in the examples but it has no graphical output
 
 #### basic_cube
 This is a rotating cube with model-space positions as colors
 
+#### compute_shader
+This renders a cube to an FBO then uses a compute shader to invert that image
+
+#### framebuffers
+This renders to a texture using and FBO
+
+#### geometry_shader
+This is a pass through geometry shader
+  
+#### geometry_shader_normal_viewer
+This is a cube geometry shader which converts faces to lines to show normals
+
 #### multiple_attributes_and_buffers
 This uses mapped buffers to upload data
 
@@ -54,65 +81,53 @@ The buffer backing the VAO is switched to change vertex data quickly
 The attribute binding could also be switched to change the vertex data quickly
 
 Interactivity: The spacebar toggles which buffer backs the active VAO 
-  
-#### compute_shader
-This renders a cube to an FBO then uses a compute shader to invert that image
-  
-#### texture
-This loads an image in the S3TC format
 
-It checks to make sure it is compressed and gets the compressed size
+#### phong_lighting
+This is a Phong lighting example
 
-#### texture_array
-This loads a jpeg image and stores it in the S3TC compressed format
+Interactivity: This implements cursor lock to control camera position
 
-It checks that it is compressed and gets the compressed size
+Mouse wheel to move forward / black
+
+#### point_sprites
+This is a very simple point sprite example
+
+#### raytracer
+A raytracer
+
+#### read_pixels
+This uses glReadnPixels and mapped Pixel Buffer Objects (to improve performance)
+
+It saves the rendered image as a .tga file
+
+Interactivity: Press spacebar to take a screenshot
 
 #### tesselation
 This compares the various tesselation spacing options
 
 Interactivity: The up arrow increases tesselation, down arrow decreases tesselationThis compares the var
-  
+
 #### tesselation_displacement_map
 This uses a displacment map to offset vertices and tesselation
 
 This uses an instanced quad with vertices embedded in the shader (there are no vertex attributes)
 
 Interactivity: `w` key toggles showing wireframeThis uses a displacment map to offset vertices and tesselation
-  
-#### transform_feedback
-This calculates the square root of some values and reads it back with transform feedback
-
-There is no graphical output
-
-#### geometry_shader
-This is a pass through geometry shader
-  
-#### geometry_shader_normal_viewer
-This is a cube geometry shader which converts faces to lines to show normals
-
-#### framebuffers
-This renders to a texture using and FBO
-  
-#### read_pixels
-This uses glReadnPixels and mapped Pixel Buffer Objects (to improve performance)
 
-It saves the rendered image as a .tga file
-
-Interactivity: Press spacebar to take a screenshot
+#### texture
+This loads an image in the S3TC format
 
-#### point_sprites
-This is a very simple point sprite example
+It checks to make sure it is compressed and gets the compressed size
 
-#### phong_lighting
-This is a Phong lighting example
+#### texture_array
+This loads a jpeg image and stores it in the S3TC compressed format
 
-Interactivity: This implements cursor lock to control camera position
+It checks that it is compressed and gets the compressed size
 
-Mouse wheel to move forward / black
+#### transform_feedback
+This calculates the square root of some values and reads it back with transform feedback
 
-#### raytracer
-A raytracer
+There is no graphical output
 
 ## Extra notes
 - To use these examples your graphics card must support at least OpenGL 4.5
@@ -122,4 +137,3 @@ A raytracer
 :copyright: Willy Nolan 2018
 
 [MIT License](http://en.wikipedia.org/wiki/MIT_License)
-

src/projects/basic_cube/src/main.cpp

@@ -62,8 +62,8 @@ class BasicCubeExample : public Application
     std::unique_ptr<GlslProgram> m_shader;
     Camera m_camera{ glm::vec3{0, 0, 5} };
     const glm::vec3 m_world_up{ glm::vec3{ 0, 1, 0 } };
-    const std::vector<GLfloat> m_clear_color { 0.2f, 0.0f, 0.2f, 1.0f };
-    const std::string m_cube_mv_matrix_name= "u_model_view_matrix";
+    const std::vector<GLfloat> m_clear_color{ 0.2f, 0.0f, 0.2f, 1.0f };
+    const std::string m_cube_mv_matrix_name = "u_model_view_matrix";
     const std::string m_cube_projection_matrix_name = "u_projection_matrix";
 
     void set_info() override

src/projects/compute_shader/src/main.cpp

@@ -59,13 +59,13 @@ static const GLfloat cube_vertices[]{
 class ComputeShaderExample : public Application
 {
 private:
-	GLuint m_cube_vao;
-	GLuint m_full_screen_quad_vao;
-	GLuint m_cube_vbo;
-	GLuint m_src_fbo;
-	GLuint m_color_texture;
-	GLuint m_depth_texture;
-	GLuint m_second_color_texture;
+	GLuint m_cube_vao{ 0 };
+	GLuint m_full_screen_quad_vao{ 0 };
+	GLuint m_cube_vbo{ 0 };
+	GLuint m_src_fbo{ 0 };
+	GLuint m_color_texture{ 0 };
+	GLuint m_depth_texture{ 0 };
+	GLuint m_second_color_texture{ 0 };
 	Camera m_camera{ glm::vec3{ 0, 0, 5 } };
 	const GLuint m_vertices_per_cube{ sizeof(cube_vertices) / sizeof(*cube_vertices) };
 	const int m_number_cubes{ 9 };
@@ -75,18 +75,19 @@ class ComputeShaderExample : public Application
 	std::unique_ptr<GlslProgram> m_cube_shader;
 	std::unique_ptr<GlslProgram> m_full_screen_quad_shader;
 	std::unique_ptr<GlslProgram> m_compute_shader;
+	const int m_workgroup_divisor { 32 };
 
-	virtual void set_info() override
+	void set_info() override
 	{
 		Application::set_info();
 		m_info.title = "Compute shader example";
 	}
 
 	void load_shaders()
 	{
-		m_cube_shader.reset(new GlslProgram{ GlslProgram::Format().vertex("../assets/shaders/cube.vert").fragment("../assets/shaders/cube.frag") });
-		m_full_screen_quad_shader.reset(new GlslProgram{ GlslProgram::Format().vertex("../assets/shaders/full_screen_quad.vert").fragment("../assets/shaders/full_screen_quad.frag") });
-		m_compute_shader.reset(new GlslProgram{ GlslProgram::Format().compute("../assets/shaders/shader.comp") });
+		m_cube_shader = std::make_unique<GlslProgram>(GlslProgram::Format().vertex("../assets/shaders/cube.vert").fragment("../assets/shaders/cube.frag"));
+		m_full_screen_quad_shader = std::make_unique<GlslProgram>(GlslProgram::Format().vertex("../assets/shaders/full_screen_quad.vert").fragment("../assets/shaders/full_screen_quad.frag"));
+		m_compute_shader = std::make_unique<GlslProgram>(GlslProgram::Format().compute("../assets/shaders/shader.comp"));
 	}
 
 	void setup_cube()
@@ -141,7 +142,7 @@ class ComputeShaderExample : public Application
 
 		// Create depth texture
 		glCreateTextures(GL_TEXTURE_2D, 1, &m_depth_texture);
-		glTextureStorage2D(m_depth_texture, 10, GL_DEPTH_COMPONENT32F, m_info.window_width, m_info.window_height);
+		glTextureStorage2D(m_depth_texture, 1, GL_DEPTH_COMPONENT32F, m_info.window_width, m_info.window_height);
 		glTextureParameteri(m_depth_texture, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 		glTextureParameteri(m_depth_texture, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 
@@ -165,14 +166,14 @@ class ComputeShaderExample : public Application
 		glCreateVertexArrays(1, &m_full_screen_quad_vao);
 	}
 
-	virtual void setup() override
+	void setup() override
 	{
 		load_shaders();
 		setup_cube();
 		setup_textures_and_buffers();
 	}
 
-	virtual void render(double current_time) override
+	void render(double current_time) override
 	{
 		// Draw scene into the src FBO
 		m_cube_shader->use();
@@ -186,6 +187,7 @@ class ComputeShaderExample : public Application
 		for (int index{ 0 }; index != m_number_cubes; ++index)
 		{
 			glm::mat4 model_matrix{ glm::mat4{ 1.0 } };
+			// Numbers here are just to offset each cube
 			model_matrix = glm::translate(model_matrix, glm::vec3{ -1.5, 0, 0 });
 			model_matrix = glm::translate(model_matrix, glm::vec3{index, static_cast<float>(index) / 5, index * -2 });
 			model_matrix = glm::rotate(model_matrix, static_cast<GLfloat>(current_time), m_world_up);
@@ -198,7 +200,7 @@ class ComputeShaderExample : public Application
 		m_compute_shader->use();
 		glBindImageTexture(0, m_color_texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA32F);
 		glBindImageTexture(1, m_second_color_texture, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RGBA32F);
-		glDispatchCompute(static_cast<GLuint>(m_info.window_width / 32), static_cast<GLuint>(m_info.window_height / 32), 1);
+		glDispatchCompute(static_cast<GLuint>(m_info.window_width / m_workgroup_divisor), static_cast<GLuint>(m_info.window_height / m_workgroup_divisor), 1);
 
 		// Draw full screen quad
 		m_full_screen_quad_shader->use();

src/projects/framebuffers/src/main.cpp

@@ -58,11 +58,12 @@ const GLfloat cube_vertices[]{
 class FboExample : public Application
 {
 private:
-	GLuint m_vao;
-	GLuint m_vbo;
-	GLuint m_fbo;
-	GLuint m_color_buffer_texture;
-	GLuint m_depth_buffer_texture;
+	GLuint m_vao { 0 };
+	GLuint m_vbo{ 0 };
+	GLuint m_fbo{ 0 };
+	GLuint m_color_buffer_texture{ 0 };
+	GLuint m_depth_buffer_texture{ 0 };
+	const float m_time_divisor { 2.0 };
 	const GLuint m_fbo_width_height{ 800 };
 	const GLuint m_num_vertices{ 36 };
 	const GLfloat m_depth_reset_val{ 1.0f };
@@ -72,11 +73,11 @@ class FboExample : public Application
 	std::unique_ptr<GlslProgram> m_shader;
 	std::unique_ptr<GlslProgram> m_shader2;
 
-	virtual void setup() override
+	void setup() override
 	{
 		// Create shaders
-		m_shader.reset(new GlslProgram{ GlslProgram::Format().vertex("../assets/shaders/cube.vert").fragment("../assets/shaders/cube.frag")});
-		m_shader2.reset(new GlslProgram{ GlslProgram::Format().vertex("../assets/shaders/cube2.vert").fragment("../assets/shaders/cube2.frag")});
+		m_shader = std::make_unique<GlslProgram>(GlslProgram::Format().vertex("../assets/shaders/cube.vert").fragment("../assets/shaders/cube.frag"));
+		m_shader2 = std::make_unique<GlslProgram>(GlslProgram::Format().vertex("../assets/shaders/cube2.vert").fragment("../assets/shaders/cube2.frag"));
 
 		// Cube vertex attribute parameters
 		const GLuint elements_per_face{ 5 };
@@ -146,7 +147,7 @@ class FboExample : public Application
         glDepthFunc(GL_LEQUAL);
 	}
 
-	virtual void render(double current_time) override
+	void render(double current_time) override
 	{
 		// Bind the member FBO
 		glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
@@ -172,7 +173,7 @@ class FboExample : public Application
 		// Set uniforms and render textured cube
 		m_shader2->use();
 		model_matrix = glm::mat4{ 1.0f };
-		model_matrix = glm::rotate(model_matrix, static_cast<GLfloat>(current_time / 2.0), m_world_up);
+		model_matrix = glm::rotate(model_matrix, static_cast<GLfloat>(current_time / m_time_divisor), m_world_up);
 		m_shader2->uniform("u_model_view_matrix", m_camera.get_view_matrix() * model_matrix);
 		m_shader2->uniform("u_projection_matrix", m_camera.get_proj_matrix());
 		glDrawArrays(GL_TRIANGLES, 0, m_num_vertices);

src/projects/geometry_shader/src/main.cpp

@@ -22,20 +22,20 @@ class GeometryShaderExample : public Application
 	const GLuint m_vertices_per_patch{ 4 };
 	const std::vector<GLfloat> m_clear_color{ 0.2f, 0.0f, 0.2f, 1.0f };
 	glm::mat4 m_model_matrix{ glm::mat4{ 1.0f } };
-	glm::mat4 m_view_matrix;
-	glm::mat4 m_projection_matrix;
+	glm::mat4 m_view_matrix{ 1.0 };
+	glm::mat4 m_projection_matrix{ 1.0 };
+	GLuint m_vao{ 0 };
+	GLuint m_vbo{ 0 };
 	Camera m_camera;
-	GLuint m_vao;
-	GLuint m_vbo;
 	std::unique_ptr<GlslProgram> m_shader;
 
-	virtual void set_info() override
+	void set_info() override
 	{
 		Application::set_info();	
 		m_info.title = "Geometry shader example";
 	}
 
-	virtual void on_key(int key, int action) override
+	void on_key(int key, int action) override
 	{
 		Application::on_key(key, action);
 		if (key == GLFW_KEY_W && action == GLFW_PRESS)
@@ -44,10 +44,10 @@ class GeometryShaderExample : public Application
 		}
 	}
 
-	virtual void setup() override
+	void setup() override
 	{
 		// Create and enable shader
-		m_shader.reset(new GlslProgram{ GlslProgram::Format().vertex("../assets/shaders/shader.vert").fragment("../assets/shaders/shader.frag").geometry("../assets/shaders/shader.geom") });
+		m_shader = std::make_unique<GlslProgram>(GlslProgram::Format().vertex("../assets/shaders/shader.vert").fragment("../assets/shaders/shader.frag").geometry("../assets/shaders/shader.geom"));
 		m_shader->use();
 
 		// Vertex attribute parameters
@@ -76,7 +76,7 @@ class GeometryShaderExample : public Application
 		glVertexArrayAttribBinding(m_vao, position_index, binding_index);
 	}
 
-	virtual void render(double current_time) override
+	void render(double current_time) override
 	{
 		// Set OpenGL state
 		glViewport(0, 0, m_info.window_width, m_info.window_height);

src/projects/geometry_shader_normal_viewer/src/main.cpp

@@ -65,8 +65,8 @@ const GLfloat cube_vertices[] {
 class GeometryShaderExample : public Application
 {
 private:
-	GLuint m_vao;
-	GLuint m_vbo;
+	GLuint m_vao{ 0 };
+	GLuint m_vbo{ 0 };
 	glm::mat4 m_model_matrix{ glm::mat4{1.0f } };
 	Camera m_camera{ glm::vec3{0, 0, 5} };
 	const GLuint m_num_vertices{ 36 };
@@ -77,17 +77,17 @@ class GeometryShaderExample : public Application
 	std::unique_ptr<GlslProgram> m_shader;
 	std::unique_ptr<GlslProgram> m_normal_shader;
 
-	virtual void set_info() override
+	void set_info() override
 	{
 		Application::set_info();
 		m_info.title = "Geometry shader example";
 	}
 
-	virtual void setup() override
+	void setup() override
 	{
 		// Create shaders
-		m_shader.reset(new GlslProgram{ GlslProgram::Format().vertex("../assets/shaders/cube.vert").fragment("../assets/shaders/cube.frag")});
-		m_normal_shader.reset(new GlslProgram{ GlslProgram::Format().vertex("../assets/shaders/normal_viewer.vert").fragment("../assets/shaders/normal_viewer.frag").geometry("../assets/shaders/normal_viewer.geom")});
+		m_shader = std::make_unique<GlslProgram>(GlslProgram::Format().vertex("../assets/shaders/cube.vert").fragment("../assets/shaders/cube.frag"));
+		m_normal_shader = std::make_unique<GlslProgram>(GlslProgram::Format().vertex("../assets/shaders/normal_viewer.vert").fragment("../assets/shaders/normal_viewer.frag").geometry("../assets/shaders/normal_viewer.geom"));
 
 		// Cube position vertex attribute parameters
         const GLuint elements_per_face{ 6 };
@@ -135,7 +135,7 @@ class GeometryShaderExample : public Application
 		glDepthFunc(GL_LEQUAL);
 	}
 
-	virtual void render(double current_time) override
+	void render(double current_time) override
 	{
 		// Set OpenGL state
 		glViewport(0, 0, m_info.window_width, m_info.window_height);