cpp/openttd-patchpack/source Changeset - r24891:054f68c6eab6

Changeset - r24891:054f68c6eab6

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0 3 1

Michael Lutz - 3 years ago 2021-01-16 15:43:20
michi@icosahedron.de

Codechange: [OpenGL] Use shaders to display the video buffer on screen.

4 files changed with 191 insertions and 1 deletions:

src/table/CMakeLists.txt

src/table/opengl_shader.h

src/video/opengl.cpp

156

src/video/opengl.h

0 comments (0 inline, 0 general)

src/table/CMakeLists.txt

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@@ @@ -85,3 +85,8 @@ add_files( @@
     unicode.h
     water_land.h
+)
 add_files(
     opengl_shader.h
     CONDITION OPENGL_FOUND
+)

src/table/opengl_shader.h

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@@ new file 100644 @@
 /* $Id$ */
 /*
  * This file is part of OpenTTD.
  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
  */
 /** @file opengl_shader.h OpenGL shader programs. */
 /** Vertex shader that just passes colour and tex coords through. */
 static const char *_vertex_shader_direct[] = {
 	"#version 110\n",
 	"void main() {",
 	"  gl_TexCoord[0] = gl_MultiTexCoord0;",
 	"  gl_Position = gl_Vertex;",
 	"}",
 };
 /** Fragment shader that reads the fragment colour from a 32bpp texture. */
 static const char *_frag_shader_direct[] = {
 	"#version 110\n",
 	"uniform sampler2D colour_tex;",
 	"void main() {",
 	"  gl_FragColor = texture2D(colour_tex, gl_TexCoord[0].st);",
 	"}",
 };

src/video/opengl.cpp

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@@ @@ -28,6 +28,9 @@ @@
 #include "../gfx_func.h"
 #include "../debug.h"
 #include "../table/opengl_shader.h"
 #include "../safeguards.h"
@@ @@ -45,6 +48,22 @@ static PFNGLGENVERTEXARRAYSPROC _glGenVe @@
 static PFNGLDELETEVERTEXARRAYSPROC _glDeleteVertexArrays;
 static PFNGLBINDVERTEXARRAYPROC _glBindVertexArray;
 static PFNGLCREATEPROGRAMPROC _glCreateProgram;
 static PFNGLDELETEPROGRAMPROC _glDeleteProgram;
 static PFNGLLINKPROGRAMPROC _glLinkProgram;
 static PFNGLUSEPROGRAMPROC _glUseProgram;
 static PFNGLGETPROGRAMIVPROC _glGetProgramiv;
 static PFNGLGETPROGRAMINFOLOGPROC _glGetProgramInfoLog;
 static PFNGLCREATESHADERPROC _glCreateShader;
 static PFNGLDELETESHADERPROC _glDeleteShader;
 static PFNGLSHADERSOURCEPROC _glShaderSource;
 static PFNGLCOMPILESHADERPROC _glCompileShader;
 static PFNGLATTACHSHADERPROC _glAttachShader;
 static PFNGLGETSHADERIVPROC _glGetShaderiv;
 static PFNGLGETSHADERINFOLOGPROC _glGetShaderInfoLog;
 static PFNGLGETUNIFORMLOCATIONPROC _glGetUniformLocation;
 static PFNGLUNIFORM1IPROC _glUniform1i;
 /** A simple 2D vertex with just position and texture. */
 struct Simple2DVertex {
 	float x, y;
@@ @@ -171,6 +190,49 @@ static bool BindVBAExtension() @@
 	return _glGenVertexArrays != nullptr && _glDeleteVertexArrays != nullptr && _glBindVertexArray != nullptr;
+}
 /** Bind extension functions for shader support. */
 static bool BindShaderExtensions()
+{
 	if (IsOpenGLVersionAtLeast(2, 0)) {
 		_glCreateProgram = (PFNGLCREATEPROGRAMPROC)GetOGLProcAddress("glCreateProgram");
 		_glDeleteProgram = (PFNGLDELETEPROGRAMPROC)GetOGLProcAddress("glDeleteProgram");
 		_glLinkProgram = (PFNGLLINKPROGRAMPROC)GetOGLProcAddress("glLinkProgram");
 		_glUseProgram = (PFNGLUSEPROGRAMPROC)GetOGLProcAddress("glUseProgram");
 		_glGetProgramiv = (PFNGLGETPROGRAMIVPROC)GetOGLProcAddress("glGetProgramiv");
 		_glGetProgramInfoLog = (PFNGLGETPROGRAMINFOLOGPROC)GetOGLProcAddress("glGetProgramInfoLog");
 		_glCreateShader = (PFNGLCREATESHADERPROC)GetOGLProcAddress("glCreateShader");
 		_glDeleteShader = (PFNGLDELETESHADERPROC)GetOGLProcAddress("glDeleteShader");
 		_glShaderSource = (PFNGLSHADERSOURCEPROC)GetOGLProcAddress("glShaderSource");
 		_glCompileShader = (PFNGLCOMPILESHADERPROC)GetOGLProcAddress("glCompileShader");
 		_glAttachShader = (PFNGLATTACHSHADERPROC)GetOGLProcAddress("glAttachShader");
 		_glGetShaderiv = (PFNGLGETSHADERIVPROC)GetOGLProcAddress("glGetShaderiv");
 		_glGetShaderInfoLog = (PFNGLGETSHADERINFOLOGPROC)GetOGLProcAddress("glGetShaderInfoLog");
 		_glGetUniformLocation = (PFNGLGETUNIFORMLOCATIONPROC)GetOGLProcAddress("glGetUniformLocation");
 		_glUniform1i = (PFNGLUNIFORM1IPROC)GetOGLProcAddress("glUniform1i");
 	} else {
 		/* In the ARB extension programs and shaders are in the same object space. */
 		_glCreateProgram = (PFNGLCREATEPROGRAMPROC)GetOGLProcAddress("glCreateProgramObjectARB");
 		_glDeleteProgram = (PFNGLDELETEPROGRAMPROC)GetOGLProcAddress("glDeleteObjectARB");
 		_glLinkProgram = (PFNGLLINKPROGRAMPROC)GetOGLProcAddress("glLinkProgramARB");
 		_glUseProgram = (PFNGLUSEPROGRAMPROC)GetOGLProcAddress("glUseProgramObjectARB");
 		_glGetProgramiv = (PFNGLGETPROGRAMIVPROC)GetOGLProcAddress("glGetObjectParameterivARB");
 		_glGetProgramInfoLog = (PFNGLGETPROGRAMINFOLOGPROC)GetOGLProcAddress("glGetInfoLogARB");
 		_glCreateShader = (PFNGLCREATESHADERPROC)GetOGLProcAddress("glCreateShaderObjectARB");
 		_glDeleteShader = (PFNGLDELETESHADERPROC)GetOGLProcAddress("glDeleteObjectARB");
 		_glShaderSource = (PFNGLSHADERSOURCEPROC)GetOGLProcAddress("glShaderSourceARB");
 		_glCompileShader = (PFNGLCOMPILESHADERPROC)GetOGLProcAddress("glCompileShaderARB");
 		_glAttachShader = (PFNGLATTACHSHADERPROC)GetOGLProcAddress("glAttachObjectARB");
 		_glGetShaderiv = (PFNGLGETSHADERIVPROC)GetOGLProcAddress("glGetObjectParameterivARB");
 		_glGetShaderInfoLog = (PFNGLGETSHADERINFOLOGPROC)GetOGLProcAddress("glGetInfoLogARB");
 		_glGetUniformLocation = (PFNGLGETUNIFORMLOCATIONPROC)GetOGLProcAddress("glGetUniformLocationARB");
 		_glUniform1i = (PFNGLUNIFORM1IPROC)GetOGLProcAddress("glUniform1iARB");
+	}
 	return _glCreateProgram != nullptr && _glDeleteProgram != nullptr && _glLinkProgram != nullptr && _glGetProgramiv != nullptr && _glGetProgramInfoLog != nullptr &&
 		_glCreateShader != nullptr && _glDeleteShader != nullptr && _glShaderSource != nullptr && _glCompileShader != nullptr && _glAttachShader != nullptr &&
 		_glGetShaderiv != nullptr && _glGetShaderInfoLog != nullptr && _glGetUniformLocation != nullptr && _glUniform1i != nullptr;
+}
 /** Callback to receive OpenGL debug messages. */
 void APIENTRY DebugOutputCallback(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar *message, const void *userParam)
+{
@@ @@ -261,6 +323,9 @@ OpenGLBackend::OpenGLBackend() @@
  */
 OpenGLBackend::~OpenGLBackend()
+{
 	if (_glDeleteProgram != nullptr) {
 		_glDeleteProgram(this->vid_program);
+	}
 	if (_glDeleteVertexArrays != nullptr) _glDeleteVertexArrays(1, &this->vao_quad);
 	if (_glDeleteBuffers != nullptr) {
 		_glDeleteBuffers(1, &this->vbo_quad);
@@ @@ -302,6 +367,13 @@ const char *OpenGLBackend::Init() @@
 	/* Check for vertex array objects. */
 	if (!IsOpenGLVersionAtLeast(3, 0) && (!IsOpenGLExtensionSupported("GL_ARB_vertex_array_object") || !IsOpenGLExtensionSupported("GL_APPLE_vertex_array_object"))) return "Vertex array objects not supported";
 	if (!BindVBAExtension()) return "Failed to bind VBA extension functions";
 	/* Check for shader objects. */
 	if (!IsOpenGLVersionAtLeast(2, 0) && (!IsOpenGLExtensionSupported("GL_ARB_shader_objects") || !IsOpenGLExtensionSupported("GL_ARB_fragment_shader") || !IsOpenGLExtensionSupported("GL_ARB_vertex_shader"))) return "No shader support";
 	if (!BindShaderExtensions()) return "Failed to bind shader extension functions";
 	DEBUG(driver, 2, "OpenGL shading language version: %s", (const char *)glGetString(GL_SHADING_LANGUAGE_VERSION));
 	if (!this->InitShaders()) return "Failed to initialize shaders";
 	/* Setup video buffer texture. */
 	glGenTextures(1, &this->vid_texture);
@@ @@ -314,6 +386,11 @@ const char *OpenGLBackend::Init() @@
 	glBindTexture(GL_TEXTURE_2D, 0);
 	if (glGetError() != GL_NO_ERROR) return "Can't generate video buffer texture";
 	/* Bind texture to shader program. */
 	GLint tex_location = _glGetUniformLocation(this->vid_program, "colour_tex");
 	_glUseProgram(this->vid_program);
 	_glUniform1i(tex_location, 0); // Texture unit 0.
 	/* Create pixel buffer object as video buffer storage. */
 	_glGenBuffers(1, &this->vid_pbo);
 	_glBindBuffer(GL_PIXEL_UNPACK_BUFFER, this->vid_pbo);
@@ @@ -338,6 +415,7 @@ const char *OpenGLBackend::Init() @@
 	_glBindBuffer(GL_ARRAY_BUFFER, this->vbo_quad);
 	_glBufferData(GL_ARRAY_BUFFER, sizeof(vert_array), vert_array, GL_STATIC_DRAW);
 	if (glGetError() != GL_NO_ERROR) return "Can't generate VBO for fullscreen quad";
 	/* Set vertex state. */
 	glEnableClientState(GL_VERTEX_ARRAY);
 	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
@@ @@ -347,13 +425,89 @@ const char *OpenGLBackend::Init() @@
 	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
 	glDisable(GL_DEPTH_TEST);
 	glEnable(GL_TEXTURE_2D);
 	(void)glGetError(); // Clear errors.
 	return nullptr;
+}
 /**
  * Check a shader for compilation errors and log them if necessary.
  * @param shader Shader to check.
  * @return True if the shader is valid.
  */
 static bool VerifyShader(GLuint shader)
+{
 	static ReusableBuffer<char> log_buf;
 	GLint result = GL_FALSE;
 	_glGetShaderiv(shader, GL_COMPILE_STATUS, &result);
 	/* Output log if there is one. */
 	GLint log_len = 0;
 	_glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &log_len);
 	if (log_len > 0) {
 		_glGetShaderInfoLog(shader, log_len, nullptr, log_buf.Allocate(log_len));
 		DEBUG(driver, result != GL_TRUE ? 0 : 2, "%s", log_buf.GetBuffer()); // Always print on failure.
+	}
 	return result == GL_TRUE;
+}
 /**
  * Check a program for link errors and log them if necessary.
  * @param program Program to check.
  * @return True if the program is valid.
  */
 static bool VerifyProgram(GLuint program)
+{
 	static ReusableBuffer<char> log_buf;
 	GLint result = GL_FALSE;
 	_glGetProgramiv(program, GL_LINK_STATUS, &result);
 	/* Output log if there is one. */
 	GLint log_len = 0;
 	_glGetProgramiv(program, GL_INFO_LOG_LENGTH, &log_len);
 	if (log_len > 0) {
 		_glGetProgramInfoLog(program, log_len, nullptr, log_buf.Allocate(log_len));
 		DEBUG(driver, result != GL_TRUE ? 0 : 2, "%s", log_buf.GetBuffer()); // Always print on failure.
+	}
 	return result == GL_TRUE;
+}
 /**
  * Create all needed shader programs.
  * @return True if successful, false otherwise.
  */
 bool OpenGLBackend::InitShaders()
+{
 	/* Create vertex shader. */
 	GLuint vert_shader = _glCreateShader(GL_VERTEX_SHADER);
 	_glShaderSource(vert_shader, lengthof(_vertex_shader_direct), _vertex_shader_direct, nullptr);
 	_glCompileShader(vert_shader);
 	if (!VerifyShader(vert_shader)) return false;
 	/* Create fragment shader. */
 	GLuint frag_shader = _glCreateShader(GL_FRAGMENT_SHADER);
 	_glShaderSource(frag_shader, lengthof(_frag_shader_direct), _frag_shader_direct, nullptr);
 	_glCompileShader(frag_shader);
 	if (!VerifyShader(frag_shader)) return false;
 	/* Link shaders to program. */
 	this->vid_program = _glCreateProgram();
 	_glAttachShader(this->vid_program, vert_shader);
 	_glAttachShader(this->vid_program, frag_shader);
 	_glLinkProgram(this->vid_program);
 	if (!VerifyProgram(this->vid_program)) return false;
 	_glDeleteShader(vert_shader);
 	_glDeleteShader(frag_shader);
 	return true;
+}
 /**
  * Change the size of the drawing window and allocate matching resources.
  * @param w New width of the window.
  * @param h New height of the window.
@@ @@ -393,6 +547,7 @@ void OpenGLBackend::Paint() @@
 	/* Blit video buffer to screen. */
 	glBindTexture(GL_TEXTURE_2D, this->vid_texture);
 	_glUseProgram(this->vid_program);
 	_glBindVertexArray(this->vao_quad);
 	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+}

src/video/opengl.h

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@@ @@ -28,6 +28,7 @@ private: @@
 	GLuint vid_pbo;     ///< Pixel buffer object storing the memory used for the video driver to draw to.
 	GLuint vid_texture; ///< Texture handle for the video buffer texture.
 	GLuint vid_program; ///< Shader program for rendering the video buffer.
 	GLuint vao_quad;    ///< Vertex array object storing the rendering state for the fullscreen quad.
 	GLuint vbo_quad;    ///< Vertex buffer with a fullscreen quad.
@@ @@ -35,6 +36,7 @@ private: @@
 	~OpenGLBackend();
 	const char *Init();
 	bool InitShaders();
 public:
 	/** Get singleton instance of this class. */

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