Codechange: [OpenGL] Use GLSL version 1.50 if available.

2 files changed, 32 insertions, 2 deletions

diff --git a/src/table/opengl_shader.h b/src/table/opengl_shader.h
index c59bcbcab..e3d5e0b3a 100644
--- a/src/table/opengl_shader.h
+++ b/src/table/opengl_shader.h
@@ -20,6 +20,17 @@ static const char *_vertex_shader_direct[] = {
 	"}",
 };
 
+/** GLSL 1.50 vertex shader that just passes colour and tex coords through. */
+static const char *_vertex_shader_direct_150[] = {
+	"#version 150\n",
+	"in vec2 position, colour_uv;",
+	"out vec2 colour_tex_uv;",
+	"void main() {",
+	"  colour_tex_uv = colour_uv;",
+	"  gl_Position = vec4(position, 0.0, 1.0);",
+	"}",
+};
+
 /** Fragment shader that reads the fragment colour from a 32bpp texture. */
 static const char *_frag_shader_direct[] = {
 	"#version 110\n",
@@ -29,3 +40,14 @@ static const char *_frag_shader_direct[] = {
 	"  gl_FragColor = texture2D(colour_tex, colour_tex_uv);",
 	"}",
 };
+
+/** GLSL 1.50 fragment shader that reads the fragment colour from a 32bpp texture. */
+static const char *_frag_shader_direct_150[] = {
+	"#version 150\n",
+	"uniform sampler2D colour_tex;",
+	"in vec2 colour_tex_uv;",
+	"out vec4 colour;",
+	"void main() {",
+	"  colour = texture(colour_tex, colour_tex_uv);",
+	"}",
+};
diff --git a/src/video/opengl.cpp b/src/video/opengl.cpp
index 2f92b2717..b5ce12dee 100644
--- a/src/video/opengl.cpp
+++ b/src/video/opengl.cpp
@@ -500,15 +500,23 @@ static bool VerifyProgram(GLuint program)
  */
 bool OpenGLBackend::InitShaders()
 {
+	const char *ver = (const char *)glGetString(GL_SHADING_LANGUAGE_VERSION);
+	if (ver == nullptr) return false;
+
+	int glsl_major  = ver[0] - '0';
+	int glsl_minor = ver[2] - '0';
+
+	bool glsl_150 = (IsOpenGLVersionAtLeast(3, 2) || glsl_major > 1 || (glsl_major == 1 && glsl_minor >= 5));
+
 	/* Create vertex shader. */
 	GLuint vert_shader = _glCreateShader(GL_VERTEX_SHADER);
-	_glShaderSource(vert_shader, lengthof(_vertex_shader_direct), _vertex_shader_direct, nullptr);
+	_glShaderSource(vert_shader, glsl_150 ? lengthof(_vertex_shader_direct_150) : lengthof(_vertex_shader_direct), glsl_150 ? _vertex_shader_direct_150 : _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);
+	_glShaderSource(frag_shader, glsl_150 ? lengthof(_frag_shader_direct_150) : lengthof(_frag_shader_direct), glsl_150 ? _frag_shader_direct_150 : _frag_shader_direct, nullptr);
 	_glCompileShader(frag_shader);
 	if (!VerifyShader(frag_shader)) return false;