opengl renders: support of gl_version_override cvar

Provides way to check render with lower officialy
reported OpenGL version.

Same as:
* MESA_GL_VERSION_OVERRIDE=4.6
* MESA_GLSL_VERSION_OVERRIDE=460

Makefile

@@ -1115,6 +1115,7 @@ REFGL3_OBJS_ := \
 	src/client/refresh/gl3/gl3_surf.o \
 	src/client/refresh/gl3/gl3_warp.o \
 	src/client/refresh/gl3/gl3_shaders.o \
+	src/client/refresh/files/glshaders.o \
 	src/client/refresh/files/mesh.o \
 	src/client/refresh/files/light.o \
 	src/client/refresh/files/surf.o \
@@ -1160,6 +1161,7 @@ REFGL4_OBJS_ := \
 	src/client/refresh/gl4/gl4_surf.o \
 	src/client/refresh/gl4/gl4_warp.o \
 	src/client/refresh/gl4/gl4_shaders.o \
+	src/client/refresh/files/glshaders.o \
 	src/client/refresh/files/mesh.o \
 	src/client/refresh/files/light.o \
 	src/client/refresh/files/surf.o \

doc/040_cvarlist.md

@@ -473,6 +473,14 @@ Set `0` by default.
   Other supported values: `GL_NEAREST_MIPMAP_NEAREST`,
   `GL_NEAREST_MIPMAP_LINEAR`, `GL_LINEAR_MIPMAP_LINEAR`
 
+* **gl_version_override**: Override required by render OpenGL version,
+  should be used only for debug purpose and useful if OpenGL implementation
+  does not report required version and implements required by render extensions.
+  - `0`: check required version of OpenGL,
+  - `1`: render will try to run with OpenGL 1.0,
+  - `2`: render will try to run with OpenGL 2.0,
+  - `3`: render will try to run with OpenGL 3.0,
+  - `4`: render will try to run with OpenGL 4.0.
 
 ## Graphics (OpenGL 1.4 only)
 

src/client/refresh/files/glshaders.c

@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 1997-2001 Id Software, Inc.
+ *
+ * This program 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; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * =======================================================================
+ *
+ * Shared code for generate GL shaders
+ *
+ * =======================================================================
+ */
+
+#include "../ref_shared.h"
+
+const char*
+glshader_version(int major_version, int minor_version)
+{
+#ifdef YQ2_GL3_GLES3
+	if (major_version == 2)
+	{
+		return "#version 100\nprecision mediump float;\n";
+	}
+	else if (major_version == 3)
+	{
+		switch(minor_version)
+		{
+			case 0: return "#version 300 es\nprecision mediump float;\n";
+			case 1: return "#version 310 es\nprecision mediump float;\n";
+			case 2: return "#version 320 es\nprecision mediump float;\n";
+			default: return "#version 320 es\nprecision mediump float;\n";
+		}
+	}
+#else // Desktop GL
+	if (major_version == 2)
+	{
+		switch(minor_version)
+		{
+			case 0: return "#version 110\n";
+			case 1: return "#version 120\n";
+			default: return "#version 120\n";
+		}
+	}
+	else if (major_version == 3)
+	{
+		switch(minor_version)
+		{
+			case 0: return "#version 130\n";
+			case 1: return "#version 140\n";
+			case 2: return "#version 150\n";
+			case 3: return "#version 330\n";
+			default: return "#version 330\n";
+		}
+	}
+	else if (major_version == 4)
+	{
+		switch(minor_version)
+		{
+			case 0: return "#version 400\n";
+			case 1: return "#version 410\n";
+			case 2: return "#version 420\n";
+			case 3: return "#version 430\n";
+			case 4: return "#version 440\n";
+			case 5: return "#version 450\n";
+			case 6: return "#version 460\n";
+			default: return "#version 460\n";
+		}
+	}
+#endif
+
+	/* some unknown version */
+	return "#version 100\nprecision mediump float;\n";
+}

src/client/refresh/gl1/gl1_main.c

@@ -79,6 +79,7 @@ cvar_t *r_validation;
 
 cvar_t *r_lightlevel;
 cvar_t *gl1_overbrightbits;
+cvar_t *gl_version_override;
 
 cvar_t *gl1_particle_min_size;
 cvar_t *gl1_particle_max_size;
@@ -1196,6 +1197,7 @@ R_Register(void)
 	gl1_particle_att_c = ri.Cvar_Get("gl1_particle_att_c", "0.01", CVAR_ARCHIVE);
 	gl1_particle_square = ri.Cvar_Get("gl1_particle_square", "0", CVAR_ARCHIVE);
 
+	gl_version_override = ri.Cvar_Get("gl_version_override", "0", CVAR_ARCHIVE);
 	r_modulate = ri.Cvar_Get("r_modulate", "1", CVAR_ARCHIVE);
 	r_mode = ri.Cvar_Get("r_mode", "4", CVAR_ARCHIVE);
 	gl_lightmap = ri.Cvar_Get("r_lightmap", "0", 0);

src/client/refresh/gl1/gl1_sdl.c

@@ -233,10 +233,22 @@ int RI_InitContext(void* win)
 
 	if (gl_config.major_version < 1 || (gl_config.major_version == 1 && gl_config.minor_version < 4))
 	{
-		R_Printf(PRINT_ALL, "%s(): Got an OpenGL version %d.%d context - need (at least) 1.4!\n",
+		if ((!gl_version_override->value) ||
-			__func__, gl_config.major_version, gl_config.minor_version);
+			(gl_config.major_version < gl_version_override->value))
+		{
+			R_Printf(PRINT_ALL, "%s(): Got an OpenGL version %d.%d context - need (at least) 1.4!\n",
+				__func__, gl_config.major_version, gl_config.minor_version);
+
+			return false;
+		}
+		else
+		{
+			R_Printf(PRINT_ALL, "%s(): Warning: glad only got GL version %d.%d.\n"
+				"Some functionality could be broken.\n",
+				__func__, gl_config.major_version, gl_config.minor_version);
+
+		}
 
-		return false;
 	}
 
 	// Check if we've got the requested MSAA.

src/client/refresh/gl1/header/local.h

@@ -184,6 +184,7 @@ extern cvar_t *r_lerp_list;
 extern cvar_t *r_2D_unfiltered;
 extern cvar_t *r_videos_unfiltered;
 
+extern cvar_t *gl_version_override;
 extern cvar_t *gl_lightmap;
 extern cvar_t *gl_shadows;
 extern cvar_t *gl1_stencilshadow;

src/client/refresh/gl3/gl3_main.c

@@ -80,6 +80,7 @@ const hmm_mat4 gl3_identityMat4 = {{
 }};
 
 cvar_t *gl_msaa_samples;
+cvar_t *gl_version_override;
 cvar_t *r_vsync;
 cvar_t *r_retexturing;
 cvar_t *r_maptype;
@@ -209,6 +210,7 @@ GL3_Register(void)
 	gl_drawbuffer = ri.Cvar_Get("gl_drawbuffer", "GL_BACK", 0);
 	r_vsync = ri.Cvar_Get("r_vsync", "1", CVAR_ARCHIVE);
 	gl_msaa_samples = ri.Cvar_Get ( "r_msaa_samples", "0", CVAR_ARCHIVE );
+	gl_version_override = ri.Cvar_Get ( "gl_version_override", "0", CVAR_ARCHIVE );
 	r_retexturing = ri.Cvar_Get("r_retexturing", "1", CVAR_ARCHIVE);
 	r_maptype = ri.Cvar_Get("maptype", "0", CVAR_ARCHIVE);
 	r_scale8bittextures = ri.Cvar_Get("r_scale8bittextures", "0", CVAR_ARCHIVE);

src/client/refresh/gl3/gl3_sdl.c

@@ -250,8 +250,16 @@ int GL3_PrepareForWindow(void)
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
 #else // Desktop GL
-	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+	if (gl_version_override->value)
-	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
+	{
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, gl_version_override->value);
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
+	}
+	else
+	{
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
+	}
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
 #endif
 
@@ -380,10 +388,21 @@ int GL3_InitContext(void* win)
 	else if (GLVersion.major < 3 || (GLVersion.major == 3 && GLVersion.minor < 2))
 #endif
 	{
-		R_Printf(PRINT_ALL, "%s(): ERROR: glad only got GL version %d.%d!\n",
+		if ((!gl_version_override->value) ||
-			__func__, GLVersion.major, GLVersion.minor);
+			(GLVersion.major < gl_version_override->value))
+		{
+			R_Printf(PRINT_ALL, "%s(): ERROR: glad only got GL version %d.%d!\n",
+				__func__, GLVersion.major, GLVersion.minor);
 
-		return false;
+			return false;
+		}
+		else
+		{
+			R_Printf(PRINT_ALL, "%s(): Warning: glad only got GL version %d.%d.\n"
+				"Some functionality could be broken.\n",
+				__func__, GLVersion.major, GLVersion.minor);
+
+		}
 	}
 	else
 	{

src/client/refresh/gl3/gl3_shaders.c

@@ -35,12 +35,7 @@ static GLuint
 CompileShader(GLenum shaderType, const char* shaderSrc, const char* shaderSrc2)
 {
 	GLuint shader = glCreateShader(shaderType);
-
+	const char* version = glshader_version(gl3config.major_version, gl3config.minor_version);
-#ifdef YQ2_GL3_GLES3
-	const char* version = "#version 300 es\nprecision mediump float;\n";
-#else // Desktop GL
-	const char* version = "#version 150\n";
-#endif
 	const char* sources[3] = { version, shaderSrc, shaderSrc2 };
 	int numSources = shaderSrc2 != NULL ? 3 : 2;
 

src/client/refresh/gl3/header/local.h

@@ -506,6 +506,7 @@ extern void GL3_UpdateUBOLights(void);
 // ############ Cvars ###########
 
 extern cvar_t *gl_msaa_samples;
+extern cvar_t *gl_version_override;
 extern cvar_t *r_vsync;
 extern cvar_t *r_retexturing;
 extern cvar_t *r_maptype;

src/client/refresh/gl4/gl4_main.c

@@ -76,6 +76,7 @@ const hmm_mat4 gl4_identityMat4 = {{
 }};
 
 cvar_t *gl_msaa_samples;
+cvar_t *gl_version_override;
 cvar_t *r_vsync;
 cvar_t *r_retexturing;
 cvar_t *r_maptype;
@@ -205,6 +206,7 @@ GL4_Register(void)
 	gl_drawbuffer = ri.Cvar_Get("gl_drawbuffer", "GL_BACK", 0);
 	r_vsync = ri.Cvar_Get("r_vsync", "1", CVAR_ARCHIVE);
 	gl_msaa_samples = ri.Cvar_Get ( "r_msaa_samples", "0", CVAR_ARCHIVE );
+	gl_version_override = ri.Cvar_Get ( "gl_version_override", "0", CVAR_ARCHIVE );
 	r_retexturing = ri.Cvar_Get("r_retexturing", "1", CVAR_ARCHIVE);
 	r_maptype = ri.Cvar_Get("maptype", "0", CVAR_ARCHIVE);
 	r_scale8bittextures = ri.Cvar_Get("r_scale8bittextures", "0", CVAR_ARCHIVE);

src/client/refresh/gl4/gl4_sdl.c

@@ -232,8 +232,16 @@ int GL4_PrepareForWindow(void)
 		gl4config.stencil = false;
 	}
 
-	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
+	if (gl_version_override->value)
-	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 6);
+	{
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, gl_version_override->value);
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
+	}
+	else
+	{
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
+		SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 6);
+	}
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
 
 	// Set GL context flags.
@@ -351,10 +359,21 @@ int GL4_InitContext(void* win)
 	}
 	else if (GLVersion.major < 4 || (GLVersion.major == 4 && GLVersion.minor < 6))
 	{
-		R_Printf(PRINT_ALL, "%s(): ERROR: glad only got GL version %d.%d!\n",
+		if ((!gl_version_override->value) ||
-			__func__, GLVersion.major, GLVersion.minor);
+			(GLVersion.major < gl_version_override->value))
+		{
+			R_Printf(PRINT_ALL, "%s(): ERROR: glad only got GL version %d.%d!\n",
+				__func__, GLVersion.major, GLVersion.minor);
 
-		return false;
+			return false;
+		}
+		else
+		{
+			R_Printf(PRINT_ALL, "%s(): Warning: glad only got GL version %d.%d.\n"
+				"Some functionality could be broken.\n",
+				__func__, GLVersion.major, GLVersion.minor);
+
+		}
 	}
 	else
 	{

src/client/refresh/gl4/gl4_shaders.c

@@ -35,8 +35,7 @@ static GLuint
 CompileShader(GLenum shaderType, const char* shaderSrc, const char* shaderSrc2)
 {
 	GLuint shader = glCreateShader(shaderType);
-
+	const char* version = glshader_version(gl4config.major_version, gl4config.minor_version);
-	const char* version = "#version 460\n";
 	const char* sources[3] = { version, shaderSrc, shaderSrc2 };
 	int numSources = shaderSrc2 != NULL ? 3 : 2;
 

src/client/refresh/gl4/header/local.h

@@ -496,6 +496,7 @@ extern void GL4_UpdateUBOLights(void);
 // ############ Cvars ###########
 
 extern cvar_t *gl_msaa_samples;
+extern cvar_t *gl_version_override;
 extern cvar_t *r_vsync;
 extern cvar_t *r_retexturing;
 extern cvar_t *r_maptype;

src/client/refresh/ref_shared.h

@@ -418,4 +418,7 @@ extern void R_ClearSkyBox(float skymins[2][6], float skymaxs[2][6]);
 extern void R_MakeSkyVec(float s, float t, int axis, mvtx_t* vert,
 	qboolean farsee, float sky_min, float sky_max);
 
+/* GL only code */
+extern const char* glshader_version(int major_version, int minor_version);
+
 #endif /* SRC_CLIENT_REFRESH_REF_SHARED_H_ */