Add AMD_vertex_shader_layer support

source/glad.c

@@ -1,22 +1,22 @@
 /*
 
-    OpenGL loader generated by glad 0.1.36 on Sun May 26 12:09:35 2024.
+    OpenGL loader generated by glad 0.1.36 on Sun May 26 16:07:25 2024.
 
     Language/Generator: C/C++
     Specification: gl
     APIs: gl=4.5
     Profile: core
     Extensions:
-        
+        GL_AMD_vertex_shader_layer
     Loader: True
     Local files: False
     Omit khrplatform: False
     Reproducible: False
 
     Commandline:
-        --profile="core" --api="gl=4.5" --generator="c" --spec="gl" --extensions=""
+        --profile="core" --api="gl=4.5" --generator="c" --spec="gl" --extensions="GL_AMD_vertex_shader_layer"
     Online:
-        https://glad.dav1d.de/#profile=core&language=c&specification=gl&loader=on&api=gl%3D4.5
+        https://glad.dav1d.de/#profile=core&language=c&specification=gl&loader=on&api=gl%3D4.5&extensions=GL_AMD_vertex_shader_layer
 */
 
 #include <stdio.h>
@@ -968,6 +968,7 @@ PFNGLVIEWPORTARRAYVPROC glad_glViewportArrayv = NULL;
 PFNGLVIEWPORTINDEXEDFPROC glad_glViewportIndexedf = NULL;
 PFNGLVIEWPORTINDEXEDFVPROC glad_glViewportIndexedfv = NULL;
 PFNGLWAITSYNCPROC glad_glWaitSync = NULL;
+int GLAD_GL_AMD_vertex_shader_layer = 0;
 static void load_GL_VERSION_1_0(GLADloadproc load) {
 	if(!GLAD_GL_VERSION_1_0) return;
 	glad_glCullFace = (PFNGLCULLFACEPROC)load("glCullFace");
@@ -1723,7 +1724,7 @@ static void load_GL_VERSION_4_5(GLADloadproc load) {
 }
 static int find_extensionsGL(void) {
 	if (!get_exts()) return 0;
-	(void)&has_ext;
+	GLAD_GL_AMD_vertex_shader_layer = has_ext("GL_AMD_vertex_shader_layer");
 	free_exts();
 	return 1;
 }

source/glad/glad.h

@@ -1,22 +1,22 @@
 /*
 
-    OpenGL loader generated by glad 0.1.36 on Sun May 26 12:09:35 2024.
+    OpenGL loader generated by glad 0.1.36 on Sun May 26 16:07:25 2024.
 
     Language/Generator: C/C++
     Specification: gl
     APIs: gl=4.5
     Profile: core
     Extensions:
-        
+        GL_AMD_vertex_shader_layer
     Loader: True
     Local files: False
     Omit khrplatform: False
     Reproducible: False
 
     Commandline:
-        --profile="core" --api="gl=4.5" --generator="c" --spec="gl" --extensions=""
+        --profile="core" --api="gl=4.5" --generator="c" --spec="gl" --extensions="GL_AMD_vertex_shader_layer"
     Online:
-        https://glad.dav1d.de/#profile=core&language=c&specification=gl&loader=on&api=gl%3D4.5
+        https://glad.dav1d.de/#profile=core&language=c&specification=gl&loader=on&api=gl%3D4.5&extensions=GL_AMD_vertex_shader_layer
 */
 
 
@@ -3648,6 +3648,10 @@ typedef void (APIENTRYP PFNGLTEXTUREBARRIERPROC)(void);
 GLAPI PFNGLTEXTUREBARRIERPROC glad_glTextureBarrier;
 #define glTextureBarrier glad_glTextureBarrier
 #endif
+#ifndef GL_AMD_vertex_shader_layer
+#define GL_AMD_vertex_shader_layer 1
+GLAPI int GLAD_GL_AMD_vertex_shader_layer;
+#endif
 
 #ifdef __cplusplus
 }

source/glerminal-private.h

@@ -7,6 +7,7 @@
 #include <glad/glad.h>
 #include <GLFW/glfw3.h>
 
+#include <iostream>
 #include <fstream>
 #include <stdexcept>
 

source/glerminal.cpp

@@ -52,7 +52,36 @@ namespace
 		"	gl_Position = vec4(scaled_offset.x + temp.x, scaled_offset.y - temp.y, 0, 1);\n"
 		"}";
 
+	// note: AMD_vertex_shader_layer support required
+	constexpr char VERTEX_SHADER_AMD_SOURCE[] =
+		"#version 450 core\n"
+		"#extension GL_AMD_vertex_shader_layer : enable\n"
+		"layout (location = 0) in vec2 position;\n"
+		"layout (location = 1) in vec2 offset;\n"
+		"layout (location = 2) in int sprite;\n"
+		"uniform vec4 " GRID_SIZE_UNIFORM_NAME ";\n"
+		"layout (std430, binding = 0) buffer LayerScales"
+		"{\n"
+		"	float scales[];\n"
+		"} lss;\n"
+		"out VS_OUT {\n"
+		"	flat int sprite;\n"
+		"	vec2 texcoord;\n"
+		"} vs_out;\n"
+		"void main()\n"
+		"{\n"
+		"	const int layer = int(floor(gl_InstanceID / " GRID_SIZE_UNIFORM_NAME ".y));\n"
+		"	gl_Layer = layer;\n"
+		"	vec2 scaled_offset = 2 * offset * " GRID_SIZE_UNIFORM_NAME ".zw;\n"
+		"	vs_out.sprite = sprite;\n"
+		"	vs_out.texcoord = vec2(position.x + 1, -position.y);\n"
+		"	vec2 cell_position = vec2(lss.scales[layer] + (gl_InstanceID % int(" GRID_SIZE_UNIFORM_NAME ".y)) - " GRID_SIZE_UNIFORM_NAME ".x * floor((gl_InstanceID % int(" GRID_SIZE_UNIFORM_NAME ".y)) * " GRID_SIZE_UNIFORM_NAME ".z), -floor((gl_InstanceID % int(" GRID_SIZE_UNIFORM_NAME ".y)) * " GRID_SIZE_UNIFORM_NAME ".z));\n"
+		"	vec2 temp = ((position + vec2(-0.5, 0.5)) * lss.scales[layer] + cell_position + vec2(0.5, -0.5)) * " GRID_SIZE_UNIFORM_NAME ".zw * 2 + vec2(-1, 1);\n"
+		"	gl_Position = vec4(scaled_offset.x + temp.x, scaled_offset.y - temp.y, 0, 1);\n"
+		"}";
+
 	constexpr const char* VERTEX_SHADER_SOURCE_PTR = VERTEX_SHADER_SOURCE;
+	constexpr const char* VERTEX_SHADER_AMD_SOURCE_PTR = VERTEX_SHADER_AMD_SOURCE;
 
 	constexpr char GEOMETRY_SHADER_SOURCE[] =
 		"#version 450 core\n"
@@ -98,7 +127,22 @@ namespace
 		"	FragColor = texture(" SPRITES_UNIFORM_NAME ", vec3(texcoord, sprite));\n"
 		"}";
 
+	// note: AMD_vertex_shader_layer support required
+	constexpr char FRAGMENT_SHADER_AMD_SOURCE[] =
+		"#version 450 core\n"
+		"in VS_OUT {\n"
+		"	flat int sprite;\n"
+		"	vec2 texcoord;\n"
+		"} fs_in;\n"
+		"layout (binding = 0) uniform sampler2DArray " SPRITES_UNIFORM_NAME ";\n"
+		"out vec4 FragColor;\n"
+		"void main()\n"
+		"{\n"
+		"	FragColor = texture(" SPRITES_UNIFORM_NAME ", vec3(fs_in.texcoord, fs_in.sprite));\n"
+		"}";
+
 	constexpr const char* FRAGMENT_SHADER_SOURCE_PTR = FRAGMENT_SHADER_SOURCE;
+	constexpr const char* FRAGMENT_SHADER_AMD_SOURCE_PTR = FRAGMENT_SHADER_AMD_SOURCE;
 
 	constexpr char SCREEN_VERTEX_SHADER_SOURCE[] =
 		"#version 450 core\n"
@@ -215,14 +259,12 @@ namespace glerminal
 		update_layer_colors();
 		update_layer_scales();
 
-		glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
 		glUseProgram(m_program);
 		glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer);
 		glBindVertexArray(m_vao);
 		glClear(GL_COLOR_BUFFER_BIT);
 		glDrawArraysInstanced(GL_TRIANGLES, 0, 6, GRID_AREA * LAYER_COUNT);
 
-		glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
 		glUseProgram(m_screen_program);
 		glBindFramebuffer(GL_FRAMEBUFFER, 0);
 		glBindVertexArray(m_screen_vao);
@@ -399,6 +441,7 @@ namespace glerminal
 		glDisable(GL_DEPTH_TEST);
 		glEnable(GL_BLEND);
 		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+		glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
 
 		// -- setup vertex data --
 		// create vertex buffer object
@@ -450,9 +493,12 @@ namespace glerminal
 		glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, m_layer_colors_buffer);
 
 		// -- setup shader program --
+		// test for features
+		const bool vertex_shader_layer_supported = glfwExtensionSupported("GL_AMD_vertex_shader_layer");
+
 		// compile
 		const unsigned int vertex_shader = glCreateShader(GL_VERTEX_SHADER);
-		glShaderSource(vertex_shader, 1, &VERTEX_SHADER_SOURCE_PTR, nullptr);
+		glShaderSource(vertex_shader, 1, &(vertex_shader_layer_supported ? VERTEX_SHADER_AMD_SOURCE_PTR : VERTEX_SHADER_SOURCE_PTR), nullptr);
 		glCompileShader(vertex_shader);
 
 		const unsigned int geometry_shader = glCreateShader(GL_GEOMETRY_SHADER);
@@ -460,7 +506,7 @@ namespace glerminal
 		glCompileShader(geometry_shader);
 
 		const unsigned int fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
-		glShaderSource(fragment_shader, 1, &FRAGMENT_SHADER_SOURCE_PTR, nullptr);
+		glShaderSource(fragment_shader, 1, &(vertex_shader_layer_supported ? FRAGMENT_SHADER_AMD_SOURCE_PTR : FRAGMENT_SHADER_SOURCE_PTR), nullptr);
 		glCompileShader(fragment_shader);
 
 		constexpr int INFO_LOG_SIZE = 512;
@@ -507,7 +553,11 @@ namespace glerminal
 		// link
 		m_program = glCreateProgram();
 		glAttachShader(m_program, vertex_shader);
-		glAttachShader(m_program, geometry_shader);
+		// only need geometry shader if AMD_vertex_shader_layer is not supported
+		if (!vertex_shader_layer_supported)
+		{
+			glAttachShader(m_program, geometry_shader);
+		}
 		glAttachShader(m_program, fragment_shader);
 		glLinkProgram(m_program);
 		glDeleteShader(vertex_shader);
@@ -518,6 +568,8 @@ namespace glerminal
 		glGetProgramiv(m_program, GL_LINK_STATUS, &success);
 		if (!success)
 		{
+			glGetProgramInfoLog(m_program, INFO_LOG_SIZE, nullptr, info_log);
+
 			glDeleteProgram(m_program);
 
 			throw std::runtime_error("Could not link shader program.");
@@ -673,7 +725,7 @@ void glerminal_run(glerminal_init_cb init, glerminal_main_cb main)
 	}
 	catch (const std::runtime_error& e)
 	{
-		e.what();
+		std::cout << e.what() << std::endl;
 	}
 }