Simple Shadows in GLSL, black screen

Hey all,

I've been trying to get shadows to work on my simple terrain used for testing out a realtime shader for atmospheric phenomenas. The latter works fine, but the shadowing does not.

I am using following sources of information:

[1] Paul's Projects: Shadow Mapping Tutorial For the texture matrix.
[2] Organic Vectory: Shadow Mapping Tutorial For everything else, pretty much.

I initialize my FrameBuffer, Texture, and RenderBuffer as in [2]:

void atmosphere_effect::shadow_map_init() {	shadow_map_size = 512;	shadow_map_tex = 0;	shadow_map_fb = 0;	shadow_map_rb = 0;	glGenTextures(1, &shadow_map_tex);	glBindTexture(GL_TEXTURE_2D, shadow_map_tex);	glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, shadow_map_size, shadow_map_size, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_INT, NULL);	glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_LUMINANCE);	glGenFramebuffers(1, &shadow_map_fb);	glBindFramebuffer(GL_FRAMEBUFFER, shadow_map_fb);	glGenRenderbuffers(1, &shadow_map_rb);	glBindRenderbuffer(GL_RENDERBUFFER, shadow_map_rb);	glRenderbufferStorage(GL_RENDERBUFFER, GL_RGB8, shadow_map_size, shadow_map_size);	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, shadow_map_rb);	glBindFramebuffer(GL_FRAMEBUFFER, 0);}

And render in the following way:

void atmosphere_effect::render_shadow_buffer() {	const glm::vec3 terrain_middle(0.0f, 6360.f, 0.0f);	glm::mat4 light_proj = glm::ortho(-100.f, 100.f, -100.f, 100.f, 10.f, 1000.f);	glm::mat4 light_view = glm::lookAt(terrain_middle + sun_direction_ * 400.f,	                                   terrain_middle, glm::vec3(.05f, 1, 0));	glm::mat4 bias(.5f, .0f, .0f, .0f,	               .0f, .5f, .0f, .0f,	               .0f, .0f, .5f, .0f,	               .5f, .5f, .5f, 1.f);	shadow_map_tmat = bias * light_proj * light_view;	//Save old viewport	int old_vp[4];	glGetIntegerv(GL_VIEWPORT, old_vp);	//Render   	glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);	glCullFace(GL_FRONT);    glViewport(0, 0, shadow_map_size, shadow_map_size);	glBindFramebuffer(GL_FRAMEBUFFER, shadow_map_fb);	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, shadow_map_tex, 0);	terrain_renderer_->draw(sun_direction_, light_view, light_proj * light_view);	//Restore state	glBindFramebuffer(GL_FRAMEBUFFER, 0);	glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);	glCullFace(GL_BACK);	glViewport(old_vp[0], old_vp[1], old_vp[2], old_vp[3]);}

Things to note for the above:
- I have confirmed that the light_proj and light_view matrices are good by rendering the terrain using them.
- I have cleared the color and depth buffer before rendering the shadow buffer.
- Calling the above does not mess up my state - rendering the terrain and atmosphere afterwards works correctly (except for shadowing of course).

I render my heightmap using following:

void heightmap_renderer::draw(const glm::vec3 &sun_direction, const glm::mat4 &modelview, const glm::mat4 &modelviewprojection){	m_shader->enable();		glEnable(GL_TEXTURE_2D);		/* ... setup of other textures omitted ... */	glActiveTexture(GL_TEXTURE4);	glBindTexture(GL_TEXTURE_2D, m_shadow_map_tex);	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);	/* ... setup of some uniforms omitted ... */	m_shader->set_uniform1i("shadowmap", 4);	m_shader->set_uniform("modelview", modelview);	m_shader->set_uniform("modelviewprojection", modelviewprojection);	m_shader->set_uniform("modelview_inverse", glm::inverse(modelview));	m_shader->set_uniform("shadowmat", shadow_map_tmat);	m_geom->draw();}

Things to note about the above:
- shadow_mat_tmat and m_shadow_map_tex has been properly tranfered to the heightmap_renderer class.

In my fragment shader, I test for shadows using following code in my fragment shader:

gl_FragColor = shadow2D(shadowmap, vec3(shadowmat * modelview_inverse * vec4(position, 1.0)));

Where position has been transformed with the modelview_inverse matrix in the vertex shader.

I've been on the forum looking, but I cannot find anything with close enough correspondance to what I'm doing here for it to be useful to fix a (probably) small error.

Can anyone spot what I am doing wrong? The result is always a pitch black terrain. There are no glitches or signs of z-fighting. I have tried from multiple viewpoints and multiple angles of sunlight.

Thanks :)

[Edited by - Itzelsnitch on June 29, 2010 1:35:37 PM]

Topic Locked