Class: Terrain

Inherits:
Object
  • Object
show all
Defined in:
lib/examples/GlStuff/terrain.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(surface) ⇒ Terrain

Returns a new instance of Terrain.



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# File 'lib/examples/GlStuff/terrain.rb', line 5

def initialize(surface)
	@height_map_image = surface
	@terrain_normals = Array.new
	load_from_surface()
	#compute_normals()
end

Instance Attribute Details

#height_map_image ⇒ Object

Returns the value of attribute height_map_image.



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# File 'lib/examples/GlStuff/terrain.rb', line 3

def height_map_image
  @height_map_image
end

#terrain_grid_length ⇒ Object

Returns the value of attribute terrain_grid_length.



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# File 'lib/examples/GlStuff/terrain.rb', line 3

def terrain_grid_length
  @terrain_grid_length
end

#terrain_grid_width ⇒ Object

Returns the value of attribute terrain_grid_width.



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# File 'lib/examples/GlStuff/terrain.rb', line 3

def terrain_grid_width
  @terrain_grid_width
end

#terrain_normals ⇒ Object

Returns the value of attribute terrain_normals.



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# File 'lib/examples/GlStuff/terrain.rb', line 3

def terrain_normals
  @terrain_normals
end

Instance Method Details

#compute_normals ⇒ Object 



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# File 'lib/examples/GlStuff/terrain.rb', line 125

def compute_normals
	 norm1,norm2 = Vector3.new, Vector3.new
	 @terrain_normals = Array.new(@terrain_grid_width * @terrain_grid_length * 3)

	return if @terrain_normals.nil?
	


	for i in 0..@terrain_grid_length - 1
		for j in 0..@terrain_grid_width - 1
			norm1.clear
			norm2.clear
			if i == 0 && j == 0
				norm1 = terrain_cross_product(0,0, 0,1, 1,0)
				norm1.normalize()
			elsif j == @terrain_grid_width-1 && i == @terrain_grid_length-1
				norm1 = terrain_cross_product(j,i, j,i-1, j-1,i)
				norm1.normalize()
			elsif j == 0 && i == @terrain_grid_length-1
				norm1 = terrain_cross_product(j,i, j,i-1, j+1, i)
				norm1.normalize()
			elsif j == @terrain_grid_width - 1 && i == 0
				norm1 = terrain_cross_product(j,i, j,i+1, j-1,i)
			elsif i == 0
				norm1 = terrain_cross_product(j,0, j-1,0, j,1)
				norm1.normalize
				norm2 = terrain_cross_product(j,0, j,1, j+1,0)
				norm2.normalize
				norm1 += norm2
			elsif j == 0
				norm1 = terrain_cross_product(0,i, 1,i, 0,i-1)
				norm1.normalize
				norm2 = terrain_cross_product(j,0, j,1, j+1,0)
				norm2.normalize
				norm1 += norm2
			elsif i == @terrain_grid_length-1
				norm1 = terrain_cross_product(j,i, j,i-1, j+1,i);
				norm1.normalize
				norm2 = terrain_cross_product(j,i, j+1,i, j,i-1);
				norm2.normalize
				norm1 += norm2
			elsif (j == @terrain_grid_width-1)
				norm1 = terrain_cross_product(j,i, j,i-1, j-1,i);
				norm1.normalize
				norm2 = terrain_cross_product(j,i, j-1,i, j,i+1);
				norm2.normalize
				norm1 += norm2;
			else
				norm1 = terrain_cross_product(j,i, j-1,i, j-1,i+1).unit
				norm2 = terrain_cross_product(j,i, j-1,i+1, j,i+1).unit
				norm1 += norm2;

				norm2 = terrain_cross_product(j,i, j,i+1, j+1,i+1).unit
				norm1 += norm2;
				
				norm2 = terrain_cross_product(j,i, j+1,i+1, j+1,i).unit
				norm1 += norm2

				norm2 = terrain_cross_product(j,i, j+1,i, j+1,i-1).unit
				norm1 += norm2

				norm2 = terrain_cross_product(j,i, j+1,i-1, j,i-1).unit
				norm1 += norm2

				norm2 = terrain_cross_product(j,i, j,i-1, j-1,i-1).unit
				norm1 += norm2

				norm2 = terrain_cross_product(j,i, j-1,i-1, j-1,i).unit
				norm1 += norm2
			end
			
			norm1.normalize			
			norm1.z = - norm1.z

			component = 0
			for k in 0..3 
				case k
				when 0
					component = norm1.x
				when 1
					component = norm1.y
				when 2
					component = norm1.z
				end
				@terrain_normals[3*(i*@terrain_grid_width + j) + k] = component;
			end
		end
	end
end

#create_display_list(x_offset, y_offset, z_offset) ⇒ Object 



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# File 'lib/examples/GlStuff/terrain.rb', line 55

def create_display_list(x_offset, y_offset, z_offset)
	
	start_w = (@terrain_grid_width / 2.0) - @terrain_grid_width
	start_l = (-@terrain_grid_length / 2.0) + @terrain_grid_length

	terrain_dl = glGenLists(1)
	
	glNewList(terrain_dl, GL_COMPILE)

	for i in 0..(@terrain_grid_length - 2)
		glBegin(GL_TRIANGLE_STRIP)
		for j in 0..(@terrain_grid_width - 2)

			unless @terrain_normals.empty?
				glNormal3f(@terrain_normals[3*((i+1)*@terrain_grid_width)],
						   @terrain_normals[3*((i+1)*@terrain_grid_width)+1],
						   @terrain_normals[3*((i+1)*@terrain_grid_width)+2] )
			end
			glVertex3f(
				start_w + j,
				@terrain_heights[(i+1)*@terrain_grid_width + (j)],
				start_l - (i+1)
			)			

			unless @terrain_normals.empty?
				glNormal3f(@terrain_normals[3*(i+@terrain_grid_width + j)],
						   @terrain_normals[3*(i+@terrain_grid_width + j)+1],
						   @terrain_normals[3*(i+@terrain_grid_width + j)+2] )
			end

			aux = 3 * ((i+1) * @terrain_grid_length + j)
			glVertex3f( (start_w + j),
						@terrain_heights[(i * @terrain_grid_width) + j],
						(start_l - i)
						)
		end
		glEnd()
	end

	glEndList()

	terrain_dl
end

#load_from_surface ⇒ Object 



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# File 'lib/examples/GlStuff/terrain.rb', line 12

def load_from_surface
	mode = @height_map_image.depth
	puts mode
	@terrain_grid_width = @height_map_image.width
	@terrain_grid_length = @height_map_image.height
	@terrain_heights = Array.new( @terrain_grid_width * @terrain_grid_length)
	pixels = @height_map_image.pixels()
	#puts pixels
	puts pixels.size
	for i in 0..@terrain_grid_length-1
		for j in 0..@terrain_grid_width-1
			#aux = mode * (i * @terrain_grid_width + j)
			#index = aux + (mode - 1)
			#puts@height_map_image.get_at(i,j)[1]
			#if index < pixels.size
				point_height = @height_map_image.get_at(i,j)[0] / 255.0
				#puts point_height
			#end
			@terrain_heights[i * @terrain_grid_width + j] = point_height
		end
	end

	for i in 0..10
		#puts @terrain_heights[i * 1000]
	end
end

#terrain_cross_product(x1, z1, x2, z2, x3, z3) ⇒ Object 



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# File 'lib/examples/GlStuff/terrain.rb', line 39

def terrain_cross_product(x1, z1, x2, z2, x3, z3)
	v1 = v2 =  aux = Vector3.new

	v1.x = (x2 - x1 )
	v1.y = -@terrain_heights[z1 * @terrain_grid_width + x1] + 
				@terrain_heights[z2 * @terrain_grid_width + x2]
	v1.z = (z2 - z1)

	v2.x = (x3 - x1)
	v2.y = -@terrain_heights[z1 * @terrain_grid_width + x1] + 
				@terrain_heights[z3 * @terrain_grid_width + x3]
	v2.z = (z3 - z1)

	v1 -= v1.crossProduct(v2)
end

#terrain_scale(minnum, maxnum) ⇒ Object 



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# File 'lib/examples/GlStuff/terrain.rb', line 100

def terrain_scale(minnum, maxnum)
	if minnum > maxnum
		aux = minnum
		minnum = maxnum
		maxnum = aux
	end

	amp = maxnum - minnum

	total = @terrain_grid_width * @terrain_grid_length

	min_val = @terrain_heights.min
	max_val = @terrain_heights.max
	for i in 0..total-2
		height = (@terrain_heights[i] - min_val) / (max_val -	 min_val)
		if height == nil
			next
		end
		@terrain_heights[i] = (height * amp) - minnum
		#puts @terrain_heights[i]
	end

	compute_normals()
end