Shuffle some GL state setting

Ensures the right things are set at the right times, it's more calls but its less prone
to randomly getting screwed over. Also updates the comments about which phases do what.

3 files changed, 20 insertions, 6 deletions

diff --git a/gfx/gl/sceneRenderer.cpp b/gfx/gl/sceneRenderer.cpp
index e0938f2..7aace49 100644
--- a/gfx/gl/sceneRenderer.cpp
+++ b/gfx/gl/sceneRenderer.cpp
@@ -62,7 +62,7 @@ SceneRenderer::render(const SceneProvider & scene) const
 	shader.setViewProjection(camera.getPosition(), camera.getViewProjection());
 	glViewport(0, 0, size.x, size.y);
 
-	// Geometry pass
+	// Geometry/colour pass - writes albedo, normal and position textures
 	glBindFramebuffer(GL_FRAMEBUFFER, gBuffer);
 	glEnable(GL_BLEND);
 	glEnable(GL_CULL_FACE);
@@ -73,7 +73,13 @@ SceneRenderer::render(const SceneProvider & scene) const
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 	scene.content(shader);
 
-	// Illumination pass
+	// Environment pass -
+	// * ambient - clears illumination texture - see setAmbientLight
+	// * directional - updates shadowMapper, reads normal and position, writes illumination - see setDirectionalLight
+	scene.environment(shader, *this);
+
+	// Scene lights pass -
+	// * per light - reads normal and position, writes illumination
 	glBindFramebuffer(GL_FRAMEBUFFER, gBufferIll);
 	glBlendFunc(GL_ONE, GL_ONE);
 	glActiveTexture(GL_TEXTURE0);
@@ -82,11 +88,10 @@ SceneRenderer::render(const SceneProvider & scene) const
 	glBindTexture(GL_TEXTURE_2D, gNormal);
 	glActiveTexture(GL_TEXTURE2);
 	glBindTexture(GL_TEXTURE_2D_ARRAY, shadowMapper);
-	scene.environment(shader, *this);
 	glDisable(GL_DEPTH_TEST);
 	scene.lights(shader);
 
-	// Lighting pass
+	// Composition pass - reads albedo and illumination, writes output
 	glBindFramebuffer(GL_FRAMEBUFFER, output);
 	glViewport(0, 0, size.x, size.y);
 	glCullFace(GL_BACK);
@@ -114,6 +119,13 @@ SceneRenderer::setDirectionalLight(const RGB & colour, const Direction3D & direc
 	if (colour.r > 0 || colour.g > 0 || colour.b > 0) {
 		const auto lvp = shadowMapper.update(scene, direction, camera);
 		glBindFramebuffer(GL_FRAMEBUFFER, gBufferIll);
+		glBlendFunc(GL_ONE, GL_ONE);
+		glActiveTexture(GL_TEXTURE0);
+		glBindTexture(GL_TEXTURE_2D, gPosition);
+		glActiveTexture(GL_TEXTURE1);
+		glBindTexture(GL_TEXTURE_2D, gNormal);
+		glActiveTexture(GL_TEXTURE2);
+		glBindTexture(GL_TEXTURE_2D_ARRAY, shadowMapper);
 		glViewport(0, 0, size.x, size.y);
 		dirLight.use();
 		dirLight.setDirectionalLight(colour, direction, camera.getPosition(), lvp);
diff --git a/gfx/gl/shadowMapper.cpp b/gfx/gl/shadowMapper.cpp
index 9b9e404..ff0634e 100644
--- a/gfx/gl/shadowMapper.cpp
+++ b/gfx/gl/shadowMapper.cpp
@@ -77,15 +77,18 @@ ShadowMapper::getBandViewExtents(const Camera & camera, const glm::mat4 & lightV
 ShadowMapper::Definitions
 ShadowMapper::update(const SceneProvider & scene, const Direction3D & dir, const Camera & camera) const
 {
+	glCullFace(GL_FRONT);
+	glEnable(GL_DEPTH_TEST);
+
 	ShadowStenciller shadowStenciller {dir, up};
 	for (const auto & [id, asset] : gameState->assets) {
 		if (const auto r = std::dynamic_pointer_cast<const Renderable>(asset)) {
 			r->updateStencil(shadowStenciller);
 		}
 	}
+
 	glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
 	glClear(GL_DEPTH_BUFFER_BIT);
-	glCullFace(GL_FRONT);
 	glViewport(0, 0, size.x, size.y);
 
 	const auto lightViewDir = glm::lookAt({}, dir, up);
diff --git a/gfx/gl/shadowStenciller.cpp b/gfx/gl/shadowStenciller.cpp
index 9f13808..fc3d77c 100644
--- a/gfx/gl/shadowStenciller.cpp
+++ b/gfx/gl/shadowStenciller.cpp
@@ -45,7 +45,6 @@ ShadowStenciller::renderStencil(const glTexture & stencil, const MeshBase & mesh
 	glUseProgram(shadowCaster);
 	glClear(GL_DEPTH_BUFFER_BIT);
 	glViewport(0, 0, 256, 256);
-	glEnable(GL_DEPTH_TEST);
 	const auto & centre = mesh.getDimensions().centre;
 	const auto & size = mesh.getDimensions().size;
 	const auto extentsMat