Some work towards OpenGL ES 2+ support for love 0.10.

--HG--
branch : minor

src/modules/graphics/opengl/Canvas.cpp

@@ -96,7 +96,7 @@ struct FramebufferStrategy
 	virtual void setAttachments() {}
 };
 
-struct FramebufferStrategyGL3 : public FramebufferStrategy
+struct FramebufferStrategyCorePacked : public FramebufferStrategy
 {
 	virtual GLenum createFBO(GLuint &framebuffer, GLuint texture)
 	{
@@ -218,6 +218,37 @@ struct FramebufferStrategyGL3 : public FramebufferStrategy
 	}
 };
 
+struct FramebufferStrategyCore : public FramebufferStrategyCorePacked
+{
+	virtual bool createStencil(int width, int height, int samples, GLuint &stencil)
+	{
+		// create stencil buffer
+		glDeleteRenderbuffers(1, &stencil);
+		glGenRenderbuffers(1, &stencil);
+		glBindRenderbuffer(GL_RENDERBUFFER, stencil);
+
+		if (samples > 1)
+			glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, GL_STENCIL_INDEX8, width, height);
+		else
+			glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, width, height);
+
+		glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
+								  GL_RENDERBUFFER, stencil);
+
+		glBindRenderbuffer(GL_RENDERBUFFER, 0);
+
+		// check status
+		if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+		{
+			glDeleteRenderbuffers(1, &stencil);
+			stencil = 0;
+			return false;
+		}
+
+		return true;
+	}
+};
+
 struct FramebufferStrategyPackedEXT : public FramebufferStrategy
 {
 	virtual GLenum createFBO(GLuint &framebuffer, GLuint texture)
@@ -393,11 +424,9 @@ struct FramebufferStrategyEXT : public FramebufferStrategyPackedEXT
 FramebufferStrategy *strategy = nullptr;
 
 FramebufferStrategy strategyNone;
-
-FramebufferStrategyGL3 strategyGL3;
-
+FramebufferStrategyCorePacked strategyCorePacked;
+FramebufferStrategyCore strategyCore;
 FramebufferStrategyPackedEXT strategyPackedEXT;
-
 FramebufferStrategyEXT strategyEXT;
 
 Canvas *Canvas::current = nullptr;
@@ -411,7 +440,9 @@ static void getStrategy()
 	if (!strategy)
 	{
 		if (GLAD_VERSION_3_0 || GLAD_ARB_framebuffer_object)
-			strategy = &strategyGL3;
+			strategy = &strategyCorePacked;
+		else if (GLAD_ES_VERSION_2_0)
+			strategy = &strategyCore;
 		else if (GLAD_EXT_framebuffer_object && GLAD_EXT_packed_depth_stencil)
 			strategy = &strategyPackedEXT;
 		else if (GLAD_EXT_framebuffer_object && strategyEXT.isSupported())
@@ -783,6 +814,17 @@ void Canvas::stopGrab(bool switchingToOtherCanvas)
 	if (current != this)
 		return;
 
+	if (depth_stencil != 0)
+	{
+		GLenum attachments[] = {GL_STENCIL_ATTACHMENT, GL_DEPTH_ATTACHMENT};
+
+		// Hint for the driver that it doesn't need to save these buffers.
+		if (GLAD_ES_VERSION_3_0)
+			glInvalidateFramebuffer(GL_FRAMEBUFFER, 2, attachments);
+		else if (GLAD_EXT_discard_framebuffer)
+			glDiscardFramebufferEXT(GL_FRAMEBUFFER, 2, attachments);
+	}
+
 	gl.matrices.projection.pop_back();
 
 	if (switchingToOtherCanvas)
@@ -793,7 +835,7 @@ void Canvas::stopGrab(bool switchingToOtherCanvas)
 	else
 	{
 		// bind system framebuffer.
-		strategy->bindFBO(0);
+		strategy->bindFBO(gl.getDefaultFBO());
 		current = nullptr;
 		gl.setViewport(systemViewport);
 
@@ -879,7 +921,7 @@ bool Canvas::checkCreateStencil()
 	if (current && current != this)
 		strategy->bindFBO(current->fbo);
 	else if (!current)
-		strategy->bindFBO(0);
+		strategy->bindFBO(gl.getDefaultFBO());
 
 	return success;
 }
@@ -905,7 +947,7 @@ love::image::ImageData *Canvas::getImageData(love::image::Image *image)
 	if (current)
 		strategy->bindFBO(current->fbo);
 	else
-		strategy->bindFBO(0);
+		strategy->bindFBO(gl.getDefaultFBO());
 
 	// The new ImageData now owns the pixel data, so we don't delete it here.
 	love::image::ImageData *img = image->newImageData(width, height, (void *)pixels, true);
@@ -932,7 +974,7 @@ void Canvas::getPixel(unsigned char* pixel_rgba, int x, int y)
 	if (current && current != this)
 		strategy->bindFBO(current->fbo);
 	else if (!current)
-		strategy->bindFBO(0);
+		strategy->bindFBO(gl.getDefaultFBO());
 }
 
 bool Canvas::resolveMSAA()
@@ -1088,7 +1130,7 @@ bool Canvas::isFormatSupported(Canvas::Format format)
 		supported = true;
 		break;
 	case FORMAT_RGB565:
-		supported = GLAD_VERSION_4_2 || GLAD_ARB_ES2_compatibility;
+		supported = GLAD_ES_VERSION_2_0 || GLAD_VERSION_4_2 || GLAD_ARB_ES2_compatibility;
 		break;
 	case FORMAT_RG11B10F:
 		supported = GLAD_VERSION_3_0 || GLAD_EXT_packed_float;

src/modules/graphics/opengl/Font.cpp

@@ -158,7 +158,7 @@ void Font::createTexture()
 	{
 		// Clean up before throwing.
 		gl.deleteTexture(t);
-		gl.bindTexture(0);
+		gl.bindTexture(gl.getDefaultTexture());
 		textures.pop_back();
 
 		throw love::Exception("Could not create font texture!");

src/modules/graphics/opengl/Graphics.cpp

@@ -210,7 +210,7 @@ bool Graphics::setMode(int width, int height, bool &sRGB)
 	gl.initContext();
 
 	// Does the system meet LOVE's minimum requirements for graphics?
-	if (!(GLAD_VERSION_2_0 && Shader::isSupported() && Canvas::isSupported())
+	if (!(GLAD_ES_VERSION_2_0 || (GLAD_VERSION_2_0 && Shader::isSupported() && Canvas::isSupported()))
 		&& !displayedMinReqWarning)
 	{
 		love::window::Window::MessageBoxType type = love::window::Window::MESSAGEBOX_ERROR;
@@ -331,6 +331,10 @@ void Graphics::setDebug(bool enable)
 	if (!(GLAD_VERSION_4_3 || GLAD_KHR_debug || GLAD_ARB_debug_output))
 		return;
 
+	// TODO: We don't support GL_KHR_debug in GLES yet.
+	if (GLAD_ES_VERSION_2_0)
+		return;
+
 	// Ugly hack to reduce code duplication.
 	if (GLAD_ARB_debug_output && !(GLAD_VERSION_4_3 || GLAD_KHR_debug))
 	{
@@ -396,8 +400,33 @@ void Graphics::clear(ClearType type)
 
 void Graphics::present()
 {
+	// Make sure we don't have a canvas active.
+	std::vector<Object::StrongRef<Canvas>> canvases = states.back().canvases;
+	setCanvas();
+
+	if (GLAD_ES_VERSION_3_0 || GLAD_EXT_discard_framebuffer)
+	{
+		GLenum attachments[] = {GL_STENCIL, GL_DEPTH};
+
+		if (gl.getDefaultFBO() != 0)
+		{
+			// A non-zero FBO needs different attachment enums.
+			attachments[0] = GL_STENCIL_ATTACHMENT;
+			attachments[1] = GL_DEPTH_ATTACHMENT;
+		}
+
+		// Hint for the driver that it doesn't need to save these buffers.
+		if (GLAD_ES_VERSION_3_0)
+			glInvalidateFramebuffer(GL_FRAMEBUFFER, 2, attachments);
+		else if (GLAD_EXT_discard_framebuffer)
+			glDiscardFramebufferEXT(GL_FRAMEBUFFER, 2, attachments);
+	}
+
 	currentWindow->swapBuffers();
 
+	// Restore the currently active canvas, if there is one.
+	setCanvas(canvases);
+
 	// Reset the per-frame stat counts.
 	gl.stats.drawCalls = 0;
 	Canvas::switchCount = 0;
@@ -922,6 +951,10 @@ float Graphics::getPointSize() const
 
 void Graphics::setWireframe(bool enable)
 {
+	// Not supported in OpenGL ES.
+	if (GLAD_ES_VERSION_2_0)
+		return;
+
 	glPolygonMode(GL_FRONT_AND_BACK, enable ? GL_LINE : GL_FILL);
 	states.back().wireframe = enable;
 }
@@ -1007,7 +1040,7 @@ void Graphics::printf(const std::string &str, float x, float y, float wrap, Alig
 void Graphics::point(float x, float y)
 {
 	gl.prepareDraw();
-	gl.bindTexture(0);
+	gl.bindTexture(gl.getDefaultTexture());
 	glBegin(GL_POINTS);
 	glVertex2f(x, y);
 	glEnd();
@@ -1105,7 +1138,7 @@ void Graphics::arc(DrawMode mode, float x, float y, float radius, float angle1,
 	else
 	{
 		gl.prepareDraw();
-		gl.bindTexture(0);
+		gl.bindTexture(gl.getDefaultTexture());
 		glEnableVertexAttribArray(ATTRIB_POS);
 		glVertexAttribPointer(ATTRIB_POS, 2, GL_FLOAT, GL_FALSE, 0, coords);
 		gl.drawArrays(GL_TRIANGLE_FAN, 0, points + 2);
@@ -1129,7 +1162,7 @@ void Graphics::polygon(DrawMode mode, const float *coords, size_t count)
 	else
 	{
 		gl.prepareDraw();
-		gl.bindTexture(0);
+		gl.bindTexture(gl.getDefaultTexture());
 		glEnableVertexAttribArray(ATTRIB_POS);
 		glVertexAttribPointer(ATTRIB_POS, 2, GL_FLOAT, GL_FALSE, 0, coords);
 		gl.drawArrays(GL_POLYGON, 0, count/2-1); // opengl will close the polygon for us
@@ -1207,7 +1240,11 @@ love::image::ImageData *Graphics::newScreenshot(love::image::Image *image, bool
 Graphics::RendererInfo Graphics::getRendererInfo() const
 {
 	RendererInfo info;
-	info.name = "OpenGL";
+
+	if (GLAD_ES_VERSION_2_0)
+		info.name = "OpenGL ES";
+	else
+		info.name = "OpenGL";
 
 	const char *str = (const char *) glGetString(GL_VERSION);
 	if (str)

src/modules/graphics/opengl/Image.cpp

@@ -163,6 +163,10 @@ void Image::setWrap(const Texture::Wrap &w)
 
 void Image::setMipmapSharpness(float sharpness)
 {
+	// OpenGL ES doesn't support LOD bias via glTexParameter.
+	if (!GLAD_VERSION_1_4)
+		return;
+
 	// LOD bias has the range (-maxbias, maxbias)
 	mipmapSharpness = std::min(std::max(sharpness, -maxMipmapSharpness + 0.01f), maxMipmapSharpness - 0.01f);
 
@@ -225,7 +229,7 @@ void Image::generateMipmaps()
 	// The GL_GENERATE_MIPMAP texparameter is set in loadVolatile if we don't
 	// have support for glGenerateMipmap.
 	if (flags.mipmaps && !isCompressed() &&
-		(GLAD_VERSION_3_0 || GLAD_ARB_framebuffer_object))
+		(GLAD_ES_VERSION_2_0 || GLAD_VERSION_3_0 || GLAD_ARB_framebuffer_object))
 	{
 		// Driver bug: http://www.opengl.org/wiki/Common_Mistakes#Automatic_mipmap_generation
 #if defined(LOVE_WINDOWS) || defined(LOVE_LINUX)
@@ -243,7 +247,8 @@ void Image::loadTextureFromCompressedData()
 	int count = flags.mipmaps ? cdata->getMipmapCount() : 1;
 
 	// We have to inform OpenGL if the image doesn't have all mipmap levels.
-	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, count - 1);
+	if (GLAD_ES_VERSION_3_0 || GLAD_VERSION_1_0)
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, count - 1);
 
 	for (int i = 0; i < count; i++)
 	{
@@ -283,7 +288,7 @@ bool Image::loadVolatile()
 			throw love::Exception("cannot create image: format is not supported on this system.");
 	}
 
-	if (maxMipmapSharpness == 0.0f)
+	if (maxMipmapSharpness == 0.0f && GLAD_VERSION_1_4)
 		glGetFloatv(GL_MAX_TEXTURE_LOD_BIAS, &maxMipmapSharpness);
 
 	glGenTextures(1, &texture);
@@ -300,11 +305,11 @@ bool Image::loadVolatile()
 		return true;
 	}
 
-	if (!flags.mipmaps)
+	if (!flags.mipmaps && (GLAD_ES_VERSION_3_0 || GLAD_VERSION_1_0))
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
 
 	if (flags.mipmaps && !isCompressed() &&
-		!(GLAD_VERSION_3_0 || GLAD_ARB_framebuffer_object))
+		!(GLAD_ES_VERSION_2_0 || GLAD_VERSION_3_0 || GLAD_ARB_framebuffer_object))
 	{
 		// Auto-generate mipmaps every time the texture is modified, if
 		// glGenerateMipmap isn't supported.
@@ -414,7 +419,7 @@ void Image::loadDefaultTexture()
 	GLubyte px[] = {0xFF,0xFF,0xFF,0xFF, 0xC0,0xC0,0xC0,0xFF,
 	                0xC0,0xC0,0xC0,0xFF, 0xFF,0xFF,0xFF,0xFF};
 
-	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, px);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, px);
 }
 
 void Image::drawv(const Matrix &t, const Vertex *v)

src/modules/graphics/opengl/Mesh.cpp

@@ -320,7 +320,7 @@ void Mesh::draw(float x, float y, float angle, float sx, float sy, float ox, flo
 	if (texture.get())
 		texture->predraw();
 	else
-		gl.bindTexture(0);
+		gl.bindTexture(gl.getDefaultTexture());
 
 	Matrix m;
 	m.setTransformation(x, y, angle, sx, sy, ox, oy, kx, ky);

src/modules/graphics/opengl/OpenGL.cpp

@@ -119,6 +119,8 @@ void OpenGL::setupContext()
 
 	glActiveTexture(curgltextureunit);
 
+	glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, (GLint *) &state.defaultFBO);
+
 	BlendState blend = {GL_ONE, GL_ONE, GL_ZERO, GL_ZERO, GL_FUNC_ADD};
 	setBlendState(blend);
 
@@ -142,6 +144,9 @@ void OpenGL::deInitContext()
 	if (!contextInitialized)
 		return;
 
+	glDeleteTextures(1, &state.defaultTexture);
+	state.defaultTexture = 0;
+
 	contextInitialized = false;
 }
 
@@ -155,6 +160,7 @@ void OpenGL::initVendor()
 	}
 
 	// http://feedback.wildfiregames.com/report/opengl/feature/GL_VENDOR
+	// http://stackoverflow.com/questions/2093594/opengl-extensions-available-on-different-android-devices
 	if (strstr(vstr, "ATI Technologies"))
 		vendor = VENDOR_ATI_AMD;
 	else if (strstr(vstr, "NVIDIA"))
@@ -167,6 +173,16 @@ void OpenGL::initVendor()
 		vendor = VENDOR_APPLE;
 	else if (strstr(vstr, "Microsoft"))
 		vendor = VENDOR_MICROSOFT;
+	else if (strstr(vstr, "Imagination"))
+		vendor = VENDOR_IMGTEC;
+	else if (strstr(vstr, "ARM"))
+		vendor = VENDOR_ARM;
+	else if (strstr(vstr, "Qualcomm"))
+		vendor = VENDOR_QUALCOMM;
+	else if (strstr(vstr, "Broadcom"))
+		vendor = VENDOR_BROADCOM;
+	else if (strstr(vstr, "Vivante"))
+		vendor = VENDOR_VIVANTE;
 	else
 		vendor = VENDOR_UNKNOWN;
 }
@@ -185,11 +201,14 @@ void OpenGL::initMaxValues()
 
 	glGetIntegerv(GL_MAX_TEXTURE_SIZE, &maxTextureSize);
 
-	int maxattachments = 0;
-	glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS, &maxattachments);
+	int maxattachments = 1;
+	int maxdrawbuffers = 1;
 
-	int maxdrawbuffers = 0;
-	glGetIntegerv(GL_MAX_DRAW_BUFFERS, &maxdrawbuffers);
+	if (GLAD_ES_VERSION_3_0 || GLAD_VERSION_2_0)
+	{
+		glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS, &maxattachments);
+		glGetIntegerv(GL_MAX_DRAW_BUFFERS, &maxdrawbuffers);
+	}
 
 	maxRenderTargets = std::min(maxattachments, maxdrawbuffers);
 }
@@ -211,7 +230,9 @@ void OpenGL::createDefaultTexture()
 	// shaders for untextured primitives vs images.
 
 	GLuint curtexture = state.textureUnits[state.curTextureUnit];
-	bindTexture(0);
+
+	glGenTextures(1, &state.defaultTexture);
+	bindTexture(state.defaultTexture);
 
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
@@ -220,7 +241,7 @@ void OpenGL::createDefaultTexture()
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 
 	GLubyte pix = 255;
-	glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE8, 1, 1, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, &pix);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, 1, 1, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, &pix);
 
 	bindTexture(curtexture);
 }
@@ -429,6 +450,16 @@ OpenGL::BlendState OpenGL::getBlendState() const
 	return state.blend;
 }
 
+GLuint OpenGL::getDefaultFBO() const
+{
+	return state.defaultFBO;
+}
+
+GLuint OpenGL::getDefaultTexture() const
+{
+	return state.defaultTexture;
+}
+
 void OpenGL::setTextureUnit(int textureunit)
 {
 	if (textureunit < 0 || (size_t) textureunit >= state.textureUnits.size())

src/modules/graphics/opengl/OpenGL.h

@@ -27,7 +27,8 @@
 #include "common/Matrix.h"
 
 // GLAD
-#include "libraries/glad/gladfuncs.hpp"
+//#include "libraries/glad/gladfuncs.hpp"
+#include <gladf/gladfuncs.hpp>
 
 // C++
 #include <vector>
@@ -79,6 +80,11 @@ public:
 		VENDOR_MESA_SOFT, // Software renderer.
 		VENDOR_APPLE,     // Software renderer.
 		VENDOR_MICROSOFT, // Software renderer.
+		VENDOR_IMGTEC,
+		VENDOR_ARM,
+		VENDOR_QUALCOMM,
+		VENDOR_BROADCOM,
+		VENDOR_VIVANTE,
 		VENDOR_UNKNOWN
 	};
 
@@ -242,6 +248,17 @@ public:
 	 **/
 	BlendState getBlendState() const;
 
+	/**
+	 * This will usually be 0 (system drawable), but some platforms require a
+	 * non-zero FBO for rendering.
+	 **/
+	GLuint getDefaultFBO() const;
+
+	/**
+	 * Gets the ID for love's default texture (used for "untextured" primitives.)
+	 **/
+	GLuint getDefaultTexture() const;
+
 	/**
 	 * Helper for setting the active texture unit.
 	 *
@@ -336,6 +353,9 @@ private:
 		Viewport viewport;
 		Viewport scissor;
 
+		GLuint defaultFBO;
+		GLuint defaultTexture;
+
 		BlendState blend;
 
 		// The last ID value used for pseudo-instancing.

src/modules/graphics/opengl/ParticleSystem.cpp

@@ -64,6 +64,7 @@ ParticleSystem::ParticleSystem(Texture *texture, uint32 size)
 	, pHead(nullptr)
 	, pTail(nullptr)
 	, particleVerts(nullptr)
+	, ibo(1)
 	, texture(texture)
 	, active(true)
 	, insertMode(INSERT_MODE_TOP)
@@ -112,6 +113,7 @@ ParticleSystem::ParticleSystem(const ParticleSystem &p)
 	, pHead(nullptr)
 	, pTail(nullptr)
 	, particleVerts(nullptr)
+	, ibo(p.ibo)
 	, texture(p.texture)
 	, active(p.active)
 	, insertMode(p.insertMode)
@@ -196,6 +198,7 @@ void ParticleSystem::setBufferSize(uint32 size)
 {
 	if (size == 0 || size > MAX_PARTICLES)
 		throw love::Exception("Invalid buffer size");
+	ibo = VertexIndex(size);
 	deleteBuffers();
 	createBuffers(size);
 	reset();
@@ -874,6 +877,7 @@ void ParticleSystem::draw(float x, float y, float angle, float sx, float sy, flo
 	}
 
 	texture->predraw();
+	gl.prepareDraw();
 
 	glEnableVertexAttribArray(ATTRIB_COLOR);
 	glEnableVertexAttribArray(ATTRIB_POS);
@@ -883,8 +887,10 @@ void ParticleSystem::draw(float x, float y, float angle, float sx, float sy, flo
 	glVertexAttribPointer(ATTRIB_POS, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), &particleVerts[0].x);
 	glVertexAttribPointer(ATTRIB_TEXCOORD, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), &particleVerts[0].s);
 
-	gl.prepareDraw();
-	gl.drawArrays(GL_QUADS, 0, pCount * 4);
+	{
+		VertexBuffer::Bind ibo_bind(*ibo.getVertexBuffer());
+		gl.drawElements(GL_TRIANGLES, ibo.getIndexCount(pCount), ibo.getType(), ibo.getPointer(0));
+	}
 
 	glDisableVertexAttribArray(ATTRIB_TEXCOORD);
 	glDisableVertexAttribArray(ATTRIB_POS);

src/modules/graphics/opengl/ParticleSystem.h

@@ -29,6 +29,7 @@
 #include "graphics/Color.h"
 #include "graphics/Quad.h"
 #include "Texture.h"
+#include "VertexBuffer.h"
 
 // STL
 #include <vector>
@@ -575,6 +576,9 @@ protected:
 	// array of transformed vertex data for all particles, for drawing
 	Vertex *particleVerts;
 
+	// Vertex index buffer.
+	VertexIndex ibo;
+
 	// The texture to be drawn.
 	Object::StrongRef<Texture> texture;
 

src/modules/graphics/opengl/Polyline.cpp

@@ -330,7 +330,7 @@ void Polyline::draw()
 	gl.prepareDraw();
 
 	// draw the core line
-	gl.bindTexture(0);
+	gl.bindTexture(gl.getDefaultTexture());
 	glEnableVertexAttribArray(ATTRIB_POS);
 	glVertexAttribPointer(ATTRIB_POS, 2, GL_FLOAT, GL_FALSE, 0, vertices);
 	gl.drawArrays(draw_mode, 0, vertex_count);

src/modules/graphics/opengl/Shader.cpp

@@ -129,9 +129,6 @@ GLuint Shader::compileCode(ShaderStage stage, const std::string &code)
 		break;
 	}
 
-	// clear existing errors
-	while (glGetError() != GL_NO_ERROR);
-
 	GLuint shaderid = glCreateShader(glstage);
 
 	if (shaderid == 0)
@@ -719,7 +716,7 @@ std::string Shader::getGLSLVersion()
 
 bool Shader::isSupported()
 {
-	return getGLSLVersion() >= "1.2";
+	return GLAD_ES_VERSION_2_0 || (getGLSLVersion() >= "1.2");
 }
 
 int Shader::getUniformTypeSize(GLenum type) const

src/modules/graphics/opengl/VertexBuffer.cpp

@@ -187,14 +187,10 @@ bool VertexBuffer::load(bool restore)
 	// Copy the old buffer only if 'restore' was requested.
 	const GLvoid *src = restore ? memory_map : nullptr;
 
-	while (GL_NO_ERROR != glGetError())
-		/* clear error messages */;
-
 	// Note that if 'src' is '0', no data will be copied.
 	glBufferData(getTarget(), (GLsizeiptr) getSize(), src, getUsage());
-	GLenum err = glGetError();
 
-	return (GL_NO_ERROR == err);
+	return true;
 }
 
 void VertexBuffer::unload()